Hi, How are you? My name is Dr Suresh Raghavaiah. i am a liver and pancreas surgeon and I hope to answer your question today. i am sorry that you are having these symptoms. An ultrasound can be used to see the contractability of the gall bladder if the first scan is done on a fasting state and a second scan is repeated after a meal. The GB usually contracts to empty its contents into the intestine after eating, esp a fatty meal. Unfortunately this is not a very sensitive indicator. A HIDA scan on the other hand provides real time imaging of the GB and hence can visualise the GB contracting and emptying the radio active substance given into the intestine and based on how much content it empties, the percentage contractility is measured. Your ejection of 6% is definitely on the lower side esp if the function was measured in response to a meal or a special hormone administered during the scan. I take it that they have not found any GB stones on any of your USG scans as it could explain your symptoms. I would advise you to get a amylase level done the next time you suffer a bout of back pain to rule out pancreatitis. Hope this helps and hope you start to feel better. Pl do not hesitiate to contact me for any further clarifications needed. have a great day Dr Suresh Raghavaiah