I was recently diagnosed with blood clots and have been having TIAs or mini-strokes. The other day I had an unexplained pain in the right side of my chest radiating down my right arm and into my back. I got very sick to my stomach. This feeling past after about 15mins, but reoccured later that night. I found rest helped.
With your background I would suggest seeing your doctor.
from what I hear a person can have pains just about anywhere when suffering with a heart attack. But, it could be a pulled muscle, indigestion or a host of other things.