Lower Back Pain on the Right and Left: Possible Causes

Lower back pain, especially on one side, is a very common complaint: most people experience it at least once in their lifetime. It can be caused by muscle and ligament strain, changes in the intervertebral discs and joints, and less often by diseases of the internal organs. To find the cause, the doctor asks about the nature of the pain and, if necessary, orders examinations.

Why the lower back hurts on the right or left

Back pain is one of the most common medical problems: 8 out of 10 people experience it at least once in their lifetime, about 95% experience it at some point, and five out of ten working adults experience it every year.

Most often the pain is nonspecific: in 90% of cases examinations do not find physiological causes. A typical trigger is an injury such as a muscle strain. Less common are a herniated intervertebral disc, sciatica (nerve compression), or ankylosing spondylitis, and very rarely a fracture, tumor, or infection.

Why on one side? In intervertebral disc disease, symptoms may be unilateral or bilateral and correspond to the affected area of the spine; the most common area is L4–L5 or L5–S1. Pain is divided into acute (up to 6 weeks), subacute (6–12 weeks), and chronic (more than 3 months). A dull ache in the lower back on the right or acute pain on the left is a description of a sensation, not a diagnosis.

Causes from the spine and muscles

Nonspecific pain is often associated with strain or dislocation of the muscles and ligaments of the back, and many patients cannot recall the event that caused it. Degenerative changes — spondylosis, spondylolisthesis (forward displacement of a vertebra), and spinal canal stenosis, which usually manifests after age 60; in severe form, pain in the lower back, buttocks, or legs worsens when standing and subsides when sitting.

Vertebral compression fractures occur in 4% of patients with lower back pain; risk factors include age, female sex, a history of osteoporosis, and long-term use of glucocorticoids. Lumbar disc disease is twice as common in men and more common in those who are overweight.

Less often the cause is infection: osteomyelitis, septic discitis, paravertebral or epidural abscess. Chronic pain with normal imaging may be explained by central sensitization — increased sensitivity to pain after an injury has healed.

When lower back pain is related to internal organs

Diseases and inflammation of the gallbladder, pancreas, aorta, and kidneys can cause referred pain in the back. Referred pain is felt not where the pathological process develops, so the person points to the lower back while the source lies in another organ. Tumors of the vertebrae and adjacent structures also manifest as back pain.

Features of lower back pain in women and men

Female sex is among the risk factors for vertebral compression fractures. In men, the risk of lumbar intervertebral disc disease is twice as high.

Which examinations help find the cause

First, the doctor clarifies how long the lower back has been hurting, where exactly the pain is localized, and whether there are any red flags from the list above. If necessary, imaging is ordered: radiography, MRI, myelography, or discography. This helps rule out potentially dangerous conditions — cauda equina compression, traumatic, tumor, inflammatory, and infectious lesions of the spine, osteoporosis, and diseases of the internal organs.

When lower back pain requires urgent medical attention

A routine visit to the doctor is needed if the pain does not improve after several weeks of home treatment or interferes with everyday activities. Separately — pain in the upper back, between the shoulder blades.

• unintentional weight loss;
• swelling or a change in the shape of the back;
• pain does not subside after rest or is worse at night;
• pain worsens when coughing, sneezing, or on the toilet.

An urgent appointment is needed if fever, chills, or malaise are added to the pain, and also if severe pain began suddenly and rapidly increases.

Lower back pain on the right or left by itself is not a reason to call an ambulance. Call 103 or 112 if weakness, tingling, or numbness appears in both legs, sensation is lost in the genital and anal area, control over the bladder and bowels has changed, sensations during sex or erection have changed, chest pain occurs, or the back pain began after a serious accident.

Realistically, it is like this: in most people the episode resolves within a few weeks, but recurrences occur, and some pain becomes chronic. This material is for reference and does not replace a doctor's consultation — the side of the pain and its cause are determined by an in-person examination.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer