It's been nearly ten years, and I still get anxious if anything in the chest area feels odd or uncomfortable - even if it is just sore muscles. Did you have surgery? I remember as the feeling started coming back after surgery - things in my chest were uncomfortable.
Carolyn and Margie are completely right - you should talk with your doctor. Since my surgery I've placed many calls, had several office visits and even two trips to the ER due to chest discomfort - even though I was pretty sure none of it was another heart attack. Being told it is indigestion or muscle spasms is good news!
I remember how scary it was right after the heart attack - your heart seems to beat so loudly and every little twinge makes you worried. It does get better, things will calm down soon.
Hang in there!