Hi. Thanks for your query. Read your history and understood your problem. The symptoms of abdominal pan, pelvic pain along with rectal pressure and nausea needs to be investigated properly under the care of a Gastroenterologist as you have already consulted many doctors without any relief. I would advise you the following: First all to undergo the tests of blood, urine and stool. Colonoscopy is required as you have rectal pressure. CT scan of the abdomen helps to get a diagnosis of any internal problem like gastrointestinal cancer, mass, intestinal edema and so on. If required a diagnostic Laparoscopy helps a lot. Once the diagnosis has been made, the treatment will be an easy task. Get a proper diagnosis .