I had a negative gallbladder sonogram, but have severe upper quadrant pain.?

i was awaken at 5am today with sharp right upper quadrant pain, right at the base of my ribs... the pain continued for most of the am, sometimes flarring to the point that i felt i could not take a breath or move. the pain sometimes extended to the middle of belly about 5 inches above my belly on and right below my rib cage. also the right side of my back just feels somewhat weakened. i saw my pcp at 1130am and had a gallbladder ultrasound at 2pm. the report read negative for stones, although although in 2004 i had similar symptoms and 2 large stones were noted in the gallbladder. however, there was a mention of one single gallbladder polyp. i'm not sure of the extent of the severity of that, but it has been my knowledge that polyps do not cause pain. i had an appendectomy in 1989, so that is not the culprit. i have lost about 12lbs over the past 3 weeks from lack of appetite and occional nausea/vomitting. please, what else could be causing this pain? i take prilosec 20 q d...