The Last Few Nights As I Went To Bed I

The last few nights as I went to bed I experienced a burning, stinging type pain in my chest, behind my sternum. It felt better when I sat up. I have never experienced this before. The pain also was felt in my upper abdomen. I was going to wake someone up to take me to the hospital but it did go away. I am a normal weight 58 year old female who is very active, (running, walking every day) and am not high risk for heart disease. I do have mitral valve prolapse and PAC's which I take 20 mg of Toprol for each night. My BP is normal. I was going to call my primary doctor just to let him know about my symptoms. How worried should I be? If it were a onset of a heart attack would I be fine now and able to go for a run?