I recently had an ultrasound of the gallbladder which had no gallstones or abnormalities , would it still be necessary to do a hida scan?

Possibly: A normal gallbladder ultrasound, while good news, doesn't exclude certain syndromes of gallbladder dysfunction that can cause pain. A hida scan, when combined with cholecystokinin, is useful in that this test shows how well the gallbladder empties itself of bile and whether the giving of cholecystokinin (which causes gallbladder contraction) reproduces your pain.