What are the causes of lower left side back pain?

Several possibilitie. In that region, pain can arise from a hip, spine or si joint problem. It can also be a referred pain from your abdominal or pelvic region organs as well . If the pain is getting worse or persisting over time and is bothering you, get evaluated by your doctor to start the appropriate treatment based on a correct diagnosis. A spine issue could be facet joint or a disc problem.
Refer to answer. Causes of left sided lbp are left sided sciatica, left sided sacral ilitis, and rarely left sided pelvic lesions or inflammation. We suggest refer to your physician to identify the problem and resolve the problem.

Related Questions

What could be causing my lower left side back pain. I shift in my seat constantly to avoid it?

See below. Pain that occurs from sitting could be more than one thing. It could be related to your posture. It could be related to a painful disc which typically is more bothersome when people sit. See your doc for an evaluation. Read more...

What is causing my lower left side back pain?

Degenerative changes. This could either be from degenerative disc disease, a disc herniation or from degenerative arthritis. If this is significantly limiting and/or painful then you should seek attention for this from an interventional pain management physician. Read more...