How good is a abdominal ultrasound to evaluate ruq pain? if it's normal what's the next step? blood test normal also....

Its a good workup: You have had a pretty good evaluation for your upper abdominal pain. One possibility is "Hepatic Flexure Syndrome" the collection of bowel gas at the "top" of the "bend" your colon or large bowel takes under your liver (see picture) This is hard to confirm but you might ask your doctor about gas absorbent medication and a low gas producing diet. This is a benign condition (and a little known one)