Good thing you're getting the ultrasound. You should also make sure they draw blood and check your liver function and wbc.
I had a lap chole 2 months ago, and based on what you write, it sounds very gallbladderish.
My attacks were so excruciating, I passed out, would break out into hives and swell up. When I didn't have attacks, there were times I had a dull throbbing ache. And I constantly burbed. And I used to feel my stomach rumbling as if I were hungry (but it wasn't hunger).
Anyhow, good luck w/ it all.