No, I'm not talking about the palpitating ones. It's like an ache in my chest, all the time. I think that I went way over the maximum target heart rate. I had read somewhere before (but I can't remember now, and can't find it) that if you exceed the max target heart rate, that you can bruise your heart. I was trying to find out how serious that was, but when I look it up, all I can find is things related to a physical hit in the chest, and it being sore. btw, I'm pretty sure that it's nothing serious...that I just over did it way too much, and that it's not really a big issue. I was just googling to make sure. So, does anyone know about this particular issue?