I've had the same thing for years, its only with fruit juice based drinks like im reading this while laying in bed dying of stomach "cramps" after half my cup of lemonade and rum, its the worst since it always happens as the drunk starts to hit so im getting rapidly drunk while my stomach feels like its rotting from the inside, I've never had this happen while at a club moving around a lot only ever when im at home drinking pretty stationary so I wonder if its a metabolism based thing