Sorry for the late reply - how are you now? I have constant stomach bloating and my abdomen is always distended. It's so bad that every time a doctor examines me they comment on it - some have even suspected I had a blockage, it's been that bad, but there was no blockage, just bloating!
Have you heard of gastroparesis? The forum has a support group for it:
http://www.crohnsforum.com/showthread.php?t=58833
It's a condition where your stomach empties too slowly, which can cause bloating. You'd probably also find you feel full easily and have no appetite if you have this. Recently I was in hospital and a doctor was so concerned by the size of my stomach that I was sent for a gastric emptying study, which is a test that measures the rate at which food leaves your stomach.
I think the appearance of my stomach is also affected by how thin I am - because I'm so thin, my stomach looks even more prominent because I'm so out of proportion. However, it has not caused me any breathing problems. Certain foods can make bloating worse (e.g. beans and some vegetables), though I've never found this myself, and eating several snack-sized meals a day rather than three larger ones may help.
Another possible cause of bloating can be fluid retention. There are many possible causes of fluid retention, including medication side effects. I know prednisone often causes it. Reducing your salt intake can help with this. However, fluid retention is more likely to be seen around your ankles and feet or in your face than on your stomach.