Chest pressure/not pain?

I've had an odd pressure in my chest (directly where the heart is, below the breastbone) for about two years now.  I am mostly aware of it when I lay down on my back.  It is not painful, just a sensation of pressure.  It is worse when my allergies are going or if I'm stressed about something.  It feels as if the heart (or something) is swelled against my chest.  It is very uncomfortable.  It seems to coincide with an incident two years ago when I was taking a lot of Primatene mist over a two week period while visiting someone with a cat.  For the first time I can remember (and the only) my heart when out of rhythm on the plane ride home (beating very rapidly then slowing).  I nearly fainted, then it recovered.  I realized it must be due to the epinephrine in the P.mist.  I try to use it only a few times a year now.
    I'm physically very active (30 years old) in a sport that has a lot of running/sprinting.  I have not experienced any more heart rhythm problems even when I run, but this pressure sensation persists.   Thank you for any help!!

Dan

P.S. I was born with a tiny hole in my heart that closed up early on.  I was monitored regularly (EKG?) until I was about 4 or 5 I remember.

[CCF CARDIO MD JMF]

Dear Dan,

I would have these symptoms evaluate dby your physician particularly in view of your prior congenital problem.  It sounds as though this pressure may be asthma, although i cannot be sure.  I would want to rule out other causes including cardiac.