Your lower back, which spans from the bottom of your rib cage to the top of your legs, is a hardworking thing. It supports the weight of your upper body. About 80% of people have low back pain sometime in their lives.
It's so common that it can be considered "a part of being human," says Charles Kim, MD, a specialist in pain management, physical medicine, and rehabilitation at NYU Langone Health in New York City.
One reason is that the lower back is packed with parts that can cause trouble:
Vertebrae. These five bones in your lower spine are numbered L1 through L5 ("L" stands for "lumbar").
Disks. These spongy structures between the vertebrae cushion the bones as your body moves.
Ligaments. These bands of tissue connect your vertebrae and keep them in place.
Tendons. These rope-like cords connect your muscles to your spinal column.
Nerves. Among them is the sciatic nerve, the longest nerve in your body.
What Causes Lower Back Pain?
Lifestyle causes
The cause of your backache can vary, depending on things such as your age, job, anatomy, health history, and lifestyle.
A weak 85-year-old with back pain probably doesn't have the same underlying cause as a 20-year-old construction worker, Kim says.
And, he says, in many cases, lower back pain comes and goes without a cause being found.
Many lifestyle habits can lead to back pain. These include:
- Slouching at your desk
- Lifting and pulling heavy objects with your back rather than your legs
- Having excess (extra) body weight
- Not exercising enough
- Smoking
- Wearing high heels
- Carrying an overloaded backpack
Injuries
Falling down, getting into a car accident, or even overdoing it in a weekend pickup game can cause problems with your lower back, which include:
Sprains and strains. This means you overstretch or tear your tendons or muscle. You can do this by twisting, lifting something that's too heavy, or lifting something the wrong way. The symptoms can include painful muscle contractions, called spasms. These kinds of injuries are the most common lower back pain causes.
Spine/vertebral fractures. You can break a bone in your back if it gets hit hard or you fall, especially from a great height. Such fractures are more likely, with less impact, if you have fragile bones because of osteoporosis. Osteoporosis is most common in women after menopause but can also happen in men.
Disk problems
Herniated or ruptured disks. Normal disks have rubbery centers, covered by a tougher outer layer. But with age or injury, a disk can break down and get less flexible, causing a crack in the outer layer that lets some of the softer center stick out between your vertebrae. This can also be called a slipped disk.
Bulging disks. The outer layer of your disk bulges out but doesn't crack open. A bulging disk might cause no symptoms on its own but could cause pain if it pushes up against a nerve root.
Degenerative disk disease. As the disks that separate your vertebrae wear down, your bones may start rubbing together. Age is usually the reason, but sports and injuries can be causes, too.
Cauda equina syndrome. This rare condition happens if a ruptured (damaged) disk pushes down into the nerve roots in your spine, causing pain, weakness, and trouble with bladder and bowel control. It can start suddenly and is considered a medical emergency.
Mechanical or structural problems
Radiculopathy. A spinal nerve can get pinched or inflamed. This can cause low back pain to travel (radiate) down your legs. It can also cause numbness or tingling. One type of radiculopathy is sciatica. It affects the sciatic nerve, which runs from your butt down the backs of your legs. When it's inflamed, you may have burning or pain that can feel like an electrical shock and can go all the way down to your feet.
Spondylolisthesis. In this condition, a vertebra slips out of place and pinches spinal nerves.
Spinal stenosis. Your spinal column may narrow over time, putting pressure on your nerves. Your legs may feel numb and grow weaker.
Scoliosis . Your spine can be curved, usually beginning in childhood or teen years. This can lead to pain.
Sacroiliac joint problems. This joint sits at the bottom of your spine, on either side of your pelvis. It transfers the weight of your upper body to your lower body. This can start to bother you after you've been injured, if you have an infection or arthritis, or if you're pregnant. Abnormal movement of the joint, during a fall or other accident, can also cause long-term pain.
Arthritis
Osteoarthritis. This is the most common kind of arthritis, which happens when your cartilage and bone begin to break down and there's inflammation. It can affect your lower back.
Ankylosing spondylitis. This is a type of inflammatory arthritis that affects the joints and ligaments along your spine. The damage shows up on X-rays.
Non-radiographic axial spondyloarthritis. This is related to ankylosing spondylitis. It causes the same painful symptoms, but damage to your joints and spine doesn't show up on X-rays. It may or may not progress to visible damage.
Psoriatic arthritis. This is arthritis tied to psoriasis, a chronic skin condition. It can affect many parts of your body. You may hear it being called spondylitis if it affects your spine. It often shows up after you've had psoriasis for a while.
Other health conditions
Less commonly, back pain can be a sign of another condition, including some that need attention right away. For example:
- Infections of your vertebrae (osteomyelitis), disks (diskitis), or the joints that connect your spine to your pelvis (sacroiliitis)
- Abdominal aortic aneurysm (when the blood vessel that supplies your belly, pelvis, and legs becomes swollen)
- Kidney stones (pain in the lower back, usually just on one side)
- Tumors (though this is rare)
Fibromyalgia, a chronic condition that causes muscle pain all over your body, can also cause lower back pain.
What causes lower back pain in females?
Women and other people assigned female at birth can have some other causes of lower back pain, including:
Pregnancy. Hormonal changes, increasing weight, and a shifting center of gravity can put a strain on your lower back, especially in the later stages of pregnancy. Back pain can also be a sign of labor, including early labor.
Menstrual cramps. Some people feel pain or cramps in their backs during their periods.
Endometriosis. This painful condition is caused by the buildup of uterine tissue in places outside your uterus.
Fibroids. These noncancerous growths in your uterus can cause pain, including in your lower back.
Ovarian cysts. When a fluid-filled sac forms outside your ovary, it can cause pain in your lower back or thighs.
Pelvic inflammatory disease. This infection in your uterus can cause pain in your lower back and lower belly.
Types of Low Back Pain
If your back pain is short-term — meaning it lasts a few days or a few weeks — doctors call it acute. If it goes on for three months or more, it's considered chronic.
You may hear the term "mechanical" low back pain. That means the problem involves the moving parts of your back — disks, vertebrae, ligaments, tendons, and muscles.
Back pain also can occur on both sides or just one side of your back. When you have back pain on just the left or right side, your doctor might describe it as "unilateral." It can happen, for example, when you pull the muscles or have a medical problem, such as a kidney stone, on just one side of your body.
Other names for low back pain include lumbar syndrome and lumbago.
How your back pain feels can vary. You might describe yours as:
- Aching
- Burning
- Sharp
- Stabbing
- Dull
- Vague
It may also spread down into your butt, hips, or thighs.
Low Back Pain Risk Factors
Certain things make you more likely to have low back pain, such as:
Age. Most people first have trouble with their backs between ages 30 and 50, and the problem gets worse as they get older. That's mostly because of wear and tear.
Being out of shape. If the muscles in your belly and back are weak, they don't do as good a job of supporting the structure of your spine. You're also more likely to hurt your back if you suddenly boost your exercise or overdo activities such as snow shoveling after you've been inactive.
Obesity. Extra weight puts a strain on back muscles.
Genetics. Some causes, such as inflammatory diseases, are passed down from one of your parents.
Your job. If you have to lift, push, pull, and twist at work, you may be at risk for more back pain. Desk jobs come with their own set of problems, too. If you sit at a computer all day, you may have back pain, especially if you have poor posture.
A heavy backpack. Put your child's school backpack on the scale. If it weighs more than 20% of their weight, it's too heavy and could cause muscle strain and back pain.
When to Call the Doctor About Low Back Pain
Most back pain gets better after a few weeks. But "if you have back pain that's lingering and not getting any better after about a month, then you should see someone," probably starting with your primary care provider, Kim says.
Call your doctor right away, if you have certain red flags, such as:
- Fever, which could mean an infection
- Pain spreading down one or both legs
- Numbness or tingling in one or both legs
- Pain after a fall, car crash, or sports injury
- Trouble controlling your bowels or bladder
- New back pain when you have cancer
- Sudden weight loss
- Severe pain at night
Diagnosing the Cause of Lower Back Pain
If you see your doctor about your lower back pain, you should expect them to examine you and ask how your pain started, how it feels, and how it affects your daily activities.
They might ask you to sit, stand, walk, and lift your legs.
If you don't have any red flags, the doctor is unlikely to order any testing, Kim says.
In most cases, you'll leave the office with some advice on managing the pain and maybe some medication.
If you do have some red flags or the pain lingers, your doctor might do some tests or refer you to a specialist for testing. The goal will be to find the cause and guide you toward the right treatment.
The tests can include:
Spinal X-ray. This uses radiation to get a picture of the bones in your back. Fractures and arthritis can show up on the X-ray.
MRI or CT scans. These tests can show damaged disks or problems with bones, muscles, tissue, tendons, nerves, ligaments, and blood vessels.
Nerve studies. Electromyography (EMG) can show how your muscles respond to signals from your nerves. It can show if pressure on your nerves, from a herniated disk or other problem, might be causing your lower back pain.
Blood and urine tests. These can check for infections, kidney stones, and other possible causes.
Takeaways
Lower back pain is a common problem with many possible causes. Sometimes, the cause isn't clear and unless your pain lasts a long time or comes with concerning red flags, your doctor may not order tests to figure it out. The most common causes are muscle strains and sprains, but fractures, arthritis, and disk problems are also common causes.
Lower Back Pain Causes FAQs
What organs can cause lower back pain?
Pain in your lower back sometimes comes from surrounding organs, such as the kidneys, uterus, or colon. These kinds of problems usually cause more symptoms. For example, if you have an inflamed colon, you may also have cramps and digestive problems.
How can I tell if my lower back pain is kidney related?
If you have kidney stones or a kidney infection, the pain is probably on just one side, between the bottom of your rib cage and one hip. You may also have other symptoms, such as bloody pee, a fever, or pain when you pee.
Can weather changes cause lower back pain?
They might. Some experts say that changes in barometric pressure or temperature might cause pain in arthritic joints or add to muscle stiffness. But some research challenges those claims.
