Training Slow Down

So yesterday, during my swim my heart started to hurt.  It kinda radiated from the front to the back, or vise-verse, I just couldn't tell.  I called the cardiac nurse, and she didn't seem too concerned.  So, today I will take it easy, and see what's up.  I have an appointment with my general nurse practitioner to see if I can get a cortisone injection in my heels for my plantar-fascias, or however you spell it.  Always something.  I am a little discouraged today- that pain in the back/heart thing makes me nervous and reminds me that 7 months ago I had a heart attack.  Bleh.