Nipple pain can be both a symptom of pregnancy and a symptom before menstruation. Both are physiological responses to the development of lobular hyperplasia in the breast due to changes in estrogen and progesterone levels in the body. Some people may experience self-conscious breast fullness and pain, and it is often difficult to make an accurate judgment based on the symptoms of nipple pain alone. If you have recently had unprotected sex and have similar symptoms, and you are close to your period, you can use a pregnancy test to test for human chorionic gonadotropin in your urine more than 10 days after intercourse, or go to the hospital to have your blood tested for HCG and progesterone levels to determine if it is caused by pregnancy. However, if the nipple pain is caused by menstruation, most of them can be relieved gradually after menstruation as the hormone level in the body stabilizes.