Same symptoms I get as well... i do not have stones but have biliary dyskinesia, which causes the same thing, so still could be your gallbladder, have the do a HIDA scan... will show more in depth how your gallbladder is functioning.
You could have a type of crystals in your gallbladder. I know someone who didn't have any gallstones but it was some kind of crystalization in her gallbladder that caused a lot of pain. I had my gallbladder taken out 5 years ago and that's basically the same pain I would feel. So it's probably some kind of gallbladder issure.
Greasy foods and fatty foods like ice cream and milk products and other things (fatty meat, fried foods, etc.) can also be uncomfortable if someone might be dealing with a 'dicey' gallbladder. Even if no stones are seen the GB can still be having issues. I'd suggest you stay as far away from problematic foods as you can and see if that provides relief.