Had ultrasound done for abdomenial pain and nausea. what does minimal fullness of the right renal pelvis mean?

Probably nothing: Can reflect possible backing up of urine to kidneys from a blockage such as a stone or narrowing of ureter such as stricture.

Probably nothing: Right upper abdominal pain and nausea especially after eating are usually symptoms of gallbladder disease. If no gallstones were seen, my next step would be a hida scan to see if the gallbladder is functioning correctly. Fullness of the renal pelvis without kidney stones is probably an anatomic variant.