The symptoms of left-sided lumbar pain are as follows: 1. The clinical symptoms of left-sided lumbar pain may be caused by lumbar disc herniation, which causes changes in the pressure in the spinal canal and reflection to the lumbar region through the sinus spinal nerve. 2. The left side of the lumbar soft tissue may be repeatedly stretched, with local edema and congestion, resulting in sterile inflammation, which may lead to chronic strain on the left side of the lumbar muscles over time, resulting in soreness. 4. For women, menstrual pain during menstruation may also be caused by adnexitis, pelvic inflammatory disease, as well as left kidney stones, pelvic inflammatory disease, and pain. For women, the manifestation of menstrual pain during menstruation may also be adnexitis, pelvic inflammatory disease, as well as stones in the left kidney, stones in the left ureter or inflammation resulting in symptoms of soreness in the left lumbar side. Therefore, in this case, the patient should first rest in bed and give the corresponding topical drugs or physiotherapy symptomatic treatment. If, after resting and treatment, the symptoms do not ease within a short period of time, you must go to a regular hospital in time.