Top Causes of Left-Side Back Discomfort and When to Seek Help

Main Factors Behind Left-Side Back Discomfort

Studies show that nearly 80% of people in the United States experience discomfort on the lower left side of their back at some point. Multiple factors can contribute to this pain. Minor issues like muscle overuse often resolve on their own, but persistent pain may require medical evaluation. Here, we explore the primary causes of left-sided back pain to help you understand and take appropriate action.

Muscle Overexertion
This is a leading cause of pain on the left side of the back.

Overworking the back muscles—due to injuries, falls, or heavy lifting—can lead to pain. Often, muscle tears cause this discomfort. Healthcare professionals typically assess your medical history and look for:

Muscle weakness

Signs of muscle tears or rupture

Discomfort during movement or stretching

Localized tenderness

Generally, muscle-related left-back pain is temporary and improves within days.

Structural Concerns in the Spine
If muscle strain isn't the culprit, physicians will investigate spinal structural issues. Common causes include:

Facet joint problems

Sacroiliac joint dysfunction

Herniated lumbar disc

Diagnosis involves physical tests such as:

Neurologic examination

Leg raise test

Reflex testing

Imaging techniques like X-ray, MRI, or CT scans may be recommended to pinpoint the exact issue.

Internal Organ Conditions
Though less common, internal organ problems can cause left-side back pain, including:

Pregnancy

Pancreatitis

Kidney infections or stones

Ulcerative colitis

Gynecological issues

If internal organs are involved, reviewing recent health history is important, and imaging tests might be necessary to confirm the diagnosis.