Hi and welcome to HCM.
It really sounds like gallbladder
disorder.It doesnt need to be coused onla by stones which should be seen on CT. Galbladder motility disorders or main bile duct disorders can do it as well. Also any small bowel obstructon beneath ampulla vateri cause same symptoms and it shouldn be seen on CT. To check all of these you can do gastroscopy with ERCP and barium enema
.These are unpleasant tests but if you have persistant symptoms this is the only tests which can help. Cyst
can cause also only if presses adjacent structures. Wish you good health.