The causes of pain on the left side of the abdomen attached to the lower back include the following: 1. It may be common urinary stones, including stones in the renal pelvis, ureter, and bladder, which may cause pain in the lower back due to fluid accumulation in the kidneys, accompanied by the characteristic of radiating pain to the perineum, and serious cases of frequent urination, urgent urination, and hematuria. 2. For female patients, most of them are due to the left fallopian tubes, ovaries The actual pain is a result of the fact that the patient has a lot of pain in the left side of the fallopian tube, ovaries, and pelvic inflammatory disease, accompanied by more serious pain in the abdomen, especially in the pelvis. 3, may be due to acute and chronic colorectal inflammation appears abdominal pain, accompanied by diarrhea and other gastrointestinal symptoms, the symptoms should be promptly to the hospital to find the exact cause.