There are several possible causes of left side back pain in women: First, kidney disease, when the kidney has inflammation, tumors, stones or cysts, left side back pain can occur, then the relevant kidney ultrasound, CT examination and urine laboratory tests should be performed for early diagnosis and treatment. Second, lumbar muscle strain, when long-term use of one side of the waist for labor or work, there will be chronic injury to one side of the muscle, resulting in lumbar muscle strain, there can be symptoms of lumbar pain on one side of the waist, then we should conduct relevant examinations and physical examination to exclude other diseases for diagnosis. Third, herpes zoster, in the early stage of herpes zoster can appear on one side of the back pain, after the incubation period can appear in groups of herpes, then to the dermatology department for diagnosis and treatment. Fourth, intercostal neuralgia, patients with intercostal neuralgia can have radiating or pinprick-like pain in the lumbar intercostal nerve, which should be investigated and, if necessary, treated with nerve nutrition and closure.