When they did the ultrasound of your galbladder, all they could check for was stones. Tell your dr - or go to a gastroenterologist - that you want an endoscope done so that they can test the bial in your galbladder. Sounds very similar to what I used to experience before having my galbladder out (when I was only 21). Certain foods would cause me to be in excrutiating pain so unbearable that I could not function. They did the "usual" testing for gal stones, but found nothing, so based on my family history of galbladder disease & gal stones, the dr I was seeing decided to do an endoscope to test the bial. Sure enough, the bial was crytalizing - which eventually leads to stones - so he scheduled my surgery for that same week! Since then I have had no problems - certain foods cause some indegestion, but no pain.
I would recommend seeing a gastroenterologist and ask them about possibly checking the bial in your gal bladder, may be that you have the early stages of gal bladder disease, of course it could be something else totally, but from what your describing of your pain, it sounds just like what I went through!
Good luck, and hang in there, they'll figure it out eventually! Sometimes you just have to be pushy for them to do the tests that they need to do, especially now with the way the insurance companies "control" what they docs can and can't do! Be assertive, this is your health you're dealing with after all!!!