Low back pain and abdominal distension may occur after exertion, menstruation, chronic pelvic inflammatory disease, endometriosis, etc., generally can be relieved in about 2 to 7 days, depending on the individual. 1. Exhaustion and menstruation: back pain and abdominal distension caused by exertion and menstruation is a physiological condition, which can be relieved by resting, and may be relieved in about 2 to 5 days, depending on the individual. 2. Chronic pelvic inflammatory disease: pelvic inflammatory disease may have inflammatory exudation, which leads to lower abdominal distension, lumbosacral pain, can be treated by using antibiotics such as penicillin, cephalosporin and other drugs, usually about a week can be relieved. 3. Endometriosis: generally in the menstrual period may have a small abdominal distension, accompanied by back pain, usually after the menstrual period can be relieved. If you have a pain in the back and abdominal distension, you can seek medical treatment, the relevant drugs should be used under the guidance of the doctor. If the pain is not relieved for a long time, you need to go to the hospital to avoid delaying the treatment.