Causes of pain on the left side of the uterus are more, may be related to the following factors: 1, pelvic inflammatory disease: is the most common cause of pain on the left side of the uterus; 2, uterine fibroids, ovarian cysts, etc. can also cause pain in the uterus; 3, the left adnexa, such as the left fallopian tube, the left ovary, is in the acute stage of inflammation can also be manifested as the left side of the uterus pain; 4, the rectum in the left lower abdomen appears to be a block, or digestive function disorders caused by Constipation can also cause pain on the left side of the uterus. Once the left side of the uterus pain, should go to the hospital in time, clear cause, symptomatic treatment.