Why does my side hurt and i feel nauseous?

my right side hurts under my rib and i feel nauseous i feel like im gonna barf. Is it something i ate? All i ate was melon and coco pebles today also beef stew? i havent had the beef stew for a while could it be that? i also have gas so could it be that and it just pressure right there from the gas? why dont i feel good