Back in '00 I was having chest pains. I went to the doc and he told me that I had an upper respiratory infection and gave me some meds to take care of it. I told him is WASN'T and upper respiratory infection as I had a pain when I took a deep breath but I did not have a hard time breathing. But you know how docs are....they are right and a patient is always wrong. He gave me the meds and to come back in a week. He was off on vacation so I had to see another doc. He told me I had muscular inflammation. I explained to him that I knew what that was as I had pulled a muscle in my chest a few times before. New prescription, and come back in a week. I went through stress test, they ruled out heart problems, I pegged the breathing test where you blow into a machine to see your lung capacity. But I kept getting worse and worse. One evening, in the winter, it was down below zero outside. I had the furnace turned up but could not get warm. Went and took a hot shower trying to get warm but couldn't. I took my temp and was a tic over 103F. I told the wife I was going to the ER. They called the doctor in that was on duty that night. I explained to him that I was having severe chest pains and what the other docs had been saying for the last month and a half. I also explained to him that the chest pains were NOT muscle related, and they were not lung related. I told him that I know what a pulled chest muscle feels like as I've had it before, and I know what an upper respiratory infection is as I've also had that before, and neither one was what I was feeling. I therefore asked him very politely to listen to what I was going to tell him. I said....."it hurts to breathe. I can breathe fine, I don't wheeze, and I haven't lifted anything heavy to pull a muscle" He looked at me and said that I had the symptoms of Pericarditis. Okay...."what's that?" I had an infection that causes the Pericardal sack around the heart to start filling with fluid. When it fills, then when I take a deep breath the lungs expand, and when they do it pushed against the sack which therefore pushes against the heart, plus the heart is restricted because of the fluid buildup. If not taken care of can eventually cause death, as the night nurse told me her husband had it and she almost lost him. An ultrasound confirmed what the problem was. Four days in intensive care and a month of antibiotics took care of it.
They don't know what causes it, but since having it, I am susceptible to getting it again rather easily. Believe me, that pain is no fun at all. It does mimic the symptoms of a heart attack as the sack constricts the heart, and in doing so affects other nerves around the heart.
Hopefully they have you figured out and they get things taken care of, but just keep it in the back of your mind and you may want to ask the doc about it when you see him again.
In the meantime....relax and take it easy. If I remember correctly, you are only off work for the rest of this month, correct? Don't push things to the point you put yourself in jeopardy with your health.
The other day I came out, my shoulder wasn't feeling too bad, then I bounced around on the mower for a few hours and I wasn't worth a **** the next day because of the pain. And I have one job I HAVE to get finished up but I can't get to it until I get my press back together. My stuff just seems to snowball at times. Multi tasking......I think those days are over for me 
