I have GERD and take something daily for it. Last year I was shopping with a friend in another city when suddenly I had chest pains. I treated it as I do for GERD--relax, breathe, drink some water slowly--and it didn't improve but got worse. I found myself in an ambulance on the way to the University of Michigan hospital. Tests showed no heart problems, but through a CAT scan, they found a spot of pneumonia in the lower lobe of my lung. Evidence that pain can be referred!
If you have another incident soon, and/or start feeling "peculiar" (I realized that I had just not been feeling "right"), please get checked out more thoroughly. Many of us have learned that going through a TKR recovery period doesn't protect us from getting sick or having other physical problems! (Seems as though it should be a rule that we don't get anything else?!?! It would only be fair.)