The stomach discomfort after sex is often caused by the following reasons: first, is the time of sex, because the action is relatively rough, which causes the uterus uncoordinated contraction, so there will be uncomfortable feeling, often rest for about 10 minutes, this symptom will disappear; second, is because the pelvis has chronic inflammation, chronic inflammation makes the pelvic tissue elasticity decreased, so the stimulation of intercourse will cause discomfort in the lower abdomen. So the stimulation of intercourse will cause discomfort in the lower abdomen; thirdly, it is because of endometriosis, or pelvic tumor, which will also cause discomfort through intercourse stimulation. So it is recommended that if this happens after sex, it is best to go to the hospital to give an examination and then actively treat the cause.