Hmm...interesting. I am currently dissecting the abdomen in gross anatomy. The colon anatomy is generally fairly easy: it starts just after the terminal ileum, ascends up the right, crosses over to the left, descends down the left, then forms the s-shaped sigmoid colon into the rectum. I'd be very curious to see what a severely redundant colon looks like!
I would imagine that a CT scan would be useful in this instance. Or even an abdominal ultrasound. You have a LOT of pain, right? Am I remembering that correctly? Is it in any particular spot? When you say "upper and lower stomach," where is that in relation to your belly button? Right, left, below the ribs, below the belly button, in the middle, etc.?
Abdominal pain is a very weird thing. There are nerves from your actual stomach organs that actually land on the same place that your skin/skeletal system nerves land. This is the basis of "referred pain," because your body gets confused about which nerve (either from the organ or from the skin/skeletal area) is sending the signal. So if you have pain in the belly-button area, for instance, this tends to reflect a problem in the small intestine. Pain above the belly button and to the right can indicate problems in your liver, or further up to the right, your gallbladder.
This is not absolute, of course. It just tends to be the case. There are always exceptions. Also, sometimes pain will be felt even if there's nothing "grossly" abnormal. And that, of course, is one of the limits of medicine.