It’s common for many girls to have mild pain with their periods a couple of days each month because the uterus tightens and relaxes to move the blood out. Some girls may have other symptoms during their period such as nausea, vomiting, diarrhea, constipation, bloating in the belly area, and/or headaches. However, if your pain or other symptoms are not relieved with over-the-counter pain medicine or you miss school or activities that you normally do with your friends because of it, this could mean there is another reason for your symptoms. Ask if your mom or other relatives have been treated for endometriosis. You should make an appointment with your health care provider and get checked. Read more about painful periods (dysmenorrhea) and endometriosis.