That sounds a LOT like what I went through last year...
Ultrasound proved normal, walking seemed to help but took a lot out of me. Long periods of nausea, that got better or worse, all the pain being *very* high up... bloating etc, burping helped when I felt nauseous, to the point where I bothered my *Husband* by burping so much. He said I sounded horrible...
I was given a nexium prescription for a little while, but because it was getting pricy, I went to Prilosec until after awhile, I didn't need it anymore...
(in the meantime, I moved and left my husband) either way, the symptoms eventually went away. I guess this wouldn't help much except to say "I've been there". It still comes back occasionally, but not as bad anymore.