text: Have you ever been tested for PCOS? It can cause cyst and missed periods. About 5 to 10% of women have it and is the most common hormonal reproductive problem in women of childbearing age. Pelvic pain and infrequent menstrual periods are a symptom. You should do to a gyno and find out what is going on. If its just a Cyst they may put you on the pill to get it to leave, and to make you have a period every month so that you will not have any more.\n\nLinks about pcos:\nhttp://www.pcosupport.org/medical/whatis.php\nhttp://www.webmd.com/hw/womens_conditions/tw9104.asp