I have this, too. I just had my gallbladder removed in May and I still have the same pain. I know there isn't a gallstone still there because they looked at the time of surgery. My GI doctor has ordered a gastric emptying study and did some blood tests but I haven't heard the results yet. I don't really think it is a gastric emptying problem from what I've read about that but I don't know what it could be.
I know this is no help. I just wanted you to know you're not the only one.
I think what you are feeling is good old gas. For some reason my doctor said we have more than our share of air in our intestines. When I get this I usually take some Citracel tabs and it goes away. I've had my gallbladder studied every which way and it is functioning normally. Try thr fiber pills, they are gluten-free and I think it will bring you relief, it does for me, helps the constipation too.