Hidden pain in the left posterior lower back may be caused by physiological reasons such as poor posture, lumbar soft tissue lesions, trauma, lumbar degenerative diseases, urological diseases and other pathological reasons. 1. Physiological causes: common in sleeping or working posture caused by incorrect local muscle spasms, the patient may appear left rear lower back pain. 2. Soft tissue lesions in the lumbar region: common diseases include lumbar fasciitis, lumbar muscle strain and other diseases, and patients may experience vague pain in the left lower back. 3. Trauma: due to trauma caused by the left lower back local soft tissue injuries such as lumbar muscle sprain can lead to local injury, edema, patients may appear left lower back pain. 4. Lumbar degenerative diseases: common diseases include lumbar intervertebral disc herniation, the protruding intervertebral discs stimulate the paravertebral nerves, which can cause the patient to have vague pain in the left posterior lower back. 5. Urological diseases: common urinary tract infections and urinary stones, such as glomerulonephritis, kidney stones, ureteral stones and other diseases, patients can appear left lower back pain. Left lower back pain may also have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.