The possible causes of this symptom after ovulation are as follows: 1. A small amount of follicular fluid is discharged after the follicle ruptures during ovulation, stimulating the pelvic peritoneum and causing pain in the lower abdomen, which is a physiological reaction. 2. pelvic inflammatory disease, patients suffering from chronic pelvic inflammatory disease may have symptoms of vague pain in the lower abdomen, which may be stimulated by sexual intercourse or after ovulation. 3. Ovarian cysts can also cause vague pain in the lower abdomen, and the larger the cyst, the more obvious the symptoms. 4. Cervicitis, when suffering from chronic inflammatory diseases of the cervix, manifested as abnormal vaginal discharge, can also cause vague pain in the lower abdomen. 5. Large fibroids or a large number of them can cause vague pain in the lower abdomen due to pressure and stimulation of the uterus. The symptom of the lower abdomen may be caused by pressure and irritation of the uterus.