I agree that this is unlikely to be heart related. You could use Ibuprofen 200 to 400 mg daily 3X per day. If you have kidney or stomach problems do not use it, instead you could try tylenol, also 3X per day.
I have a chronic pain similiar to what you desribe, pain that increases or decreases with movement is seldom cardiac in origin, my pain has been diagnosed as costochrondritis, it can be very painful and is often confused with cardiac pain.This might not be the cause for your pain at all, I'm only relating my personal diagnosis and experience with a similiar experience to what you describe.