When I had severe pelvic pain which later radiated up my back, I went through the same "stuff" -- ultra sounds of kidneys, gall bladder, colonoscopy. My diagnosis was IBS and IC. Irritable Bowel Syndrome and painful Interstitial Cystitis. Are you having a problem with frequent urination? More than 8 times a day? You might try a Urologist and a gastroententologist.