For several days, I have been having like heart 'catches' or flutters , I feel it in my throat or little below my throat in center of my chest and it makes me cough...then I feel extremely tired. Also, I've had an upset stomach and unable to eat much, because I feel full, but when I eat anything, sometimes I kind of burp it up .... I have had stomach pain several times over the last five days as well. What is this?