Appendicitcs Or Peptic Ulcer?

my friend just had his appendix removed, after a few days he starts complaining of a pressure in his chest region, like sthg is pulling his heart. he belches a lot too with nausea.

is this normal with the operation or he has something else?

P.S: he said d symtoms went away for a whole day and he doesnt feel the sensation anymorw but im just wondering what the problem is.