Pain in the stomach the day after intercourse does not necessarily mean that you are pregnant at this time, but may be caused by inflammation of the pelvis or endometriosis. When the pelvic cavity is inflamed, it is congested and the tissues are slightly edematous, and after intercourse, the congestion will be aggravated, so the stomach pain will occur. Tummy pain can also occur after exertion in daily life or during menstruation. Through gynecological examination, we can find out whether there is pressure pain in the uterine adnexa, and we can know whether there is tummy pain caused by inflammation. Even after intercourse, the sperm and the egg have been united, if you are pregnant, it will not cause stomach pain, it is recommended to give a distinction, if you are planning to get pregnant, when treating pelvic inflammatory disease medication, explain to the doctor that you are in the process of preparing for pregnancy, the drugs used to consider not to affect the fetus.