Lower back pain is overwhelmingly caused by strained muscles or sprained ligaments, making it the single most common musculoskeletal complaint worldwide. In 2020, roughly 619 million people were living with it at any given time. The good news: most episodes resolve on their own within one to two weeks. But understanding what’s behind your pain helps you know when to wait it out and when to take action.
Muscle Strains and Ligament Sprains
The most likely reason your lower back hurts is a strain or sprain. A strain means you’ve pulled, twisted, or torn a muscle or tendon that supports your spine. A sprain means a ligament connecting your vertebrae has been stretched or torn. Both injuries feel similar and can happen from lifting something heavy, lifting with poor form, or even from something as minor as sneezing, coughing, or bending over at an awkward angle.
Most people with a lumbar strain or sprain improve in about two weeks. During that time, the pain typically feels like a dull ache or stiffness that worsens with movement. You might notice it’s harder to stand up straight or that certain positions make the pain spike. This type of pain usually stays in the lower back rather than traveling down your legs.
Disc Problems
Between each of your vertebrae sits a rubbery disc that acts as a shock absorber. These discs have a tough outer shell and a soft, gel-like center. Over time, or with sudden stress, the outer shell can weaken. The soft interior can bulge outward or rupture through the shell entirely. When that material presses against a nearby nerve root, you get what’s commonly called a herniated or “slipped” disc.
A herniated disc can cause pain, weakness, numbness, or tingling. If the affected nerve is the sciatic nerve, which runs from your lower back through your hips and down each leg, the pain can radiate all the way to your foot. This is sciatica, and it’s one of the clearest signs that a disc or other structure is compressing a nerve. The pain often feels sharp or burning and tends to worsen on one side.
As you age, discs also naturally lose water content and flatten out, offering less cushioning. This gradual wear is called degenerative disc disease. It’s not really a “disease” so much as a normal part of aging, though it can produce chronic, low-grade back pain in some people and no symptoms at all in others.
Spinal Stenosis and Aging
After age 50, a narrowing of the spinal canal called spinal stenosis becomes a more common source of lower back pain. Several age-related changes contribute to this narrowing. Arthritis can cause small bone spurs to grow on your vertebrae, pushing into the space where your spinal cord and nerves sit. The ligaments that hold your spine together can thicken and stiffen over time, further crowding that space. Herniated discs add to the compression.
Spinal stenosis in the lower back typically causes pain or cramping in one or both legs, especially when you stand for a long time or walk. Many people notice the pain eases when they lean forward or sit down. Some people with measurable stenosis on imaging have no symptoms at all, so the degree of narrowing doesn’t always predict how much pain you’ll feel.
When It’s Not Your Spine
Not all lower back pain starts in your back. Kidney stones are a classic example. When a stone gets stuck in the tube connecting your kidney to your bladder, it blocks urine flow and causes the kidney to swell. The result is severe, sharp pain in your side and back, below the ribs, that can spread to your lower abdomen and groin. Unlike muscular back pain, kidney stone pain comes in waves, shifts location as the stone moves, and often comes with a burning sensation when you urinate.
Kidney infections, urinary tract infections, and certain abdominal conditions can also produce pain that feels like it’s coming from the lower back. If your pain came on suddenly, feels different from typical muscle soreness, or is accompanied by fever, painful urination, or nausea, the source may not be your spine at all.
What Actually Helps
For a fresh episode of lower back pain without nerve symptoms, the American College of Physicians recommends starting with non-drug approaches: applying superficial heat, massage, acupuncture, or spinal manipulation. If you want medication, over-the-counter anti-inflammatory drugs like ibuprofen are the first choice, along with muscle relaxants if the pain involves significant muscle spasm.
Staying gently active tends to produce better outcomes than strict bed rest. Walking, light stretching, and moving within your pain tolerance helps your muscles maintain strength and flexibility while they heal.
For chronic lower back pain, meaning pain that persists beyond 12 weeks, the evidence supports a broader toolkit. Exercise is the foundation, but yoga, tai chi, cognitive behavioral therapy, mindfulness-based stress reduction, and multidisciplinary rehabilitation programs all have solid evidence behind them. Anti-inflammatory drugs remain the first-line medication option if non-drug therapies aren’t enough on their own.
Surgery for back pain is uncommon. For sciatica caused by a herniated disc, surgery is typically reserved for cases involving severe leg weakness, loss of bowel or bladder control, or pain that hasn’t responded to months of conservative treatment.
Red Flags That Need Immediate Attention
A rare but serious condition called cauda equina syndrome occurs when the bundle of nerves at the base of your spinal cord gets severely compressed. This is a surgical emergency. The warning signs are distinct from typical back pain:
- Urinary retention: your bladder fills but you don’t feel the urge to go, or you suddenly can’t control urination
- Bowel incontinence: loss of control over bowel movements
- Saddle numbness: loss of sensation in your inner thighs, buttocks, or genital area
- Progressive leg weakness: increasing difficulty moving one or both legs
- Sexual dysfunction: sudden onset alongside other symptoms
Any combination of these symptoms alongside back pain requires immediate emergency evaluation. Cauda equina syndrome can cause permanent nerve damage if not treated quickly, but with prompt surgery, outcomes are significantly better.