If you still have vague pain in the stomach 20 days after the operation, you should consider the complications related to this operation, such as residual uterine cavity and endometritis, if you did not have abdominal pain before. Of course, it does not exclude the problems unrelated to the uterine operation, which can be treated after going to the hospital for examination and clarification of the cause in time.1. Pain before menstruation: If you had dysmenorrhea in the past and are about to have menstruation 20 days after this uterine operation, you may have dysmenorrhea, which can be primary dysmenorrhea or dysmenorrhea caused by adenomyosis. If the dysmenorrhea is mild, it can be relieved by applying heat to the abdomen and drinking hot soup. If the pain is severe, it is recommended to seek medical advice and take ibuprofen, ketoprofen and other drugs for relief. 2. Uterine cavity residue: if there is residual blood or tissue in the uterine cavity after abortion, irregular vaginal bleeding will occur, accompanied by bouts of abdominal pain. The diagnosis should be confirmed by ultrasound examination at the hospital, and medical advice can be given on the use of pro-uterine contraction drugs such as motherwort, and if necessary, the uterus can be cleared again; 3, endometritis: there can be persistent abdominal pain, lumbago, lower abdominal distension with high fever and other symptoms, routine blood and cervical secretions and drug sensitivity tests are feasible, and the diagnosis can be confirmed with the application of cefuroxime and metronidazole anti-inflammatory treatment; 4, other: in addition to gynecological lesions, the abdominal pain symptoms alone 4, other: in addition to gynecological lesions, abdominal pain symptoms alone may be related to gastrointestinal lesions, or urinary stones and other conditions, the specific cause of the disease requires medical treatment.