Hi welcome to HCM... You are having history of this complaint after eating pizza that may contain cheese like dairy product ... So you might have lactose intolerance if having similar complaint after eating other dairy product .. Moreover pizza can t easily digested by stomach ...So overeating of pizza avoided ....... Try to limit dairy product if having intolerance to lactose diet Take pantoprazole for one week ... Take more fruits and fiber foods like apple , spinach , whole grain , wheat bran etc... Take more fluid and avoid smoking ... If needed lactase tablet and probiotic might help... Excess pizza not taken as they delay gastric emptying also ... Take care Advise : Gastroenterologist consultation for examination....