It is possible for left-sided back pain to be caused by a problem with one or more internal organs, such as from the kidney or colon.
Several common internal causes of lower left back pain include:
- Kidney Stones. Lower left back pain from a kidney stone may be felt when a stone moves inside the left kidney, or moves through the ureters, thin tubes connecting the kidneys to the bladder. Other symptoms include pain with urination, difficulty urinating despite a persistent need to do so, blood in the urine, and nausea and/or vomiting.
- Kidney Infection. An infection in the left kidney can cause dull or intense lower left back pain. Kidney infections usually start in the urinary tract and bladder, and from there can spread to the kidneys, causing local inflammation and pain in the kidney. Additional symptoms may include fever, nausea and/or vomiting, and painful or stinging urination. Pain is typically felt next to the spine above the hip, and typically worsens with movement or pressure.
- Gynecological Disorders. Fibroids and endometriosis, two common conditions in women, can cause lower left back pain. Pain from endometriosis is usually sporadic, sharp and stabbing, and is caused by excess uterine tissue growing outside the uterus. Other symptoms many include abdominal pain, fatigue, and severe pain with menstruation. Fibroids—typically benign masses growing in the uterus—can cause lower left back pain, as well as abnormal menstruation, frequent urination, and pain with intercourse.