Lot of possibilities
Anatomically, the right upper quadrant (RUQ) of the abdomen includes: liver, gallbladder, pancreatic head, bile
ducts and ampulla, c-loop of the duodenum, stomach antrum and pylorus, the hepatic flexure of the colon
Don't forget the diaphragm and lower chest are pretty close by. The abdominal musculature, ribs, and skin can all contribute as well to localizing RUQ pain. An exam is appropriate.