Dear sir,it is hard to believe that all these medicines cant help you. Did they think of parastomal hernia. it doesnt need to be seen on CT. If you have such a persistent pain then revision of ileostomy should be done. Complete colon removal is a mutilating procedure and many complications can be expected but the source of pain must be evaluated. Diagnostic laparoscopy can be preformed. But also this could be neuopathic pain so you can consult with your neurologist what to take. There are medicines szch as Lyrica which can be helpful. Wish you good health.