Crampy aching premenstrual pain as you describe is common, and most women who experience it have no difficulty conceiving. Even in women who experience pain severe enough to request a laparoscopy, the pelvis often appears totally normal. Having said this, there are some causes of pelvic pain which can be associated with subfertility. The most common would be endometriosis, but chronic pelvic infection also causes pain. Pains are not thought to be caused by hormone problems, although reducing the natural hormone cycle with the oral contraceptive pill often reduces period pain.