Constant bloating, burping, gas, constipation, back pain. i've ct scan, x-ray, ultra sound, blood test and all normal. what else could it be. help?

Check you diet: If every organic cause for the symptoms you describe has been ruled out (No enzyme deficiency, gluten sensitivity, GI infections etc), then you need to have a balanced diet containing appropriate amounts of proteins (meat, white and red), carbohydrates (sugars, starch), fats, fruits, vegetables and minerals (get extra magnesium: tablets from the health store)

Constipation: All of your symptoms could be attributable to constipation and the air problems may be related to how you eat and swallow air. I suspect your doc has come to the same conclusion. I would treat the constipation aggressively first and see how things improve after a month or so.