What Causes Shortness Of Breath And Muscle Pull Around Breasts?

I am a 52 year old woman...feeling a bit short of breath, and a feeling like a pulled muscle in between my breasts. I m not sure if I m having an anxiety attack, or a heart attack. I m walking around, but haven t been able to settle down to sleep. It is almost 1am. I did take two baby aspirin about an hour ago, but I don t feel any different. Are there other symptoms you can tell me to help me decide what to do? I live alone, my son is about 30 minutes away if I were to call him to have him take me to hospital. But don t want to feel silly.