Hi, Im swedish so u might not understand me that well. But i ll try. It hurts a lil in my left chest/ breast and it happend more extreme after i went on my bike. I usually work out normally like 4days/week, (im 15 y old) and now i havent worked out in 5days until today when i took my bike to the gym, it hurted in my heart so i decided not to go into the gym. Some ppl say it muscle issue, but i havent worked out anything so it cant be that i used them too much, what do u think?