Have you ever been examined by a gynecologist to be considered for having "endometriosis"? It can be any where all through the pelvis and/or body and can cause malfunction of the intestines as well as the gynecological system. It can cause severe pain all the time as wel as extremely painful periods. It may also have other symptoms as well, like fatigue, headaches, etc. But it doesn't have to; it is different for everyone. Just sounds like it might be worth looking in to if you haven't already.