Do you think i have something wrong with my heart?

I am 16. I am lean, able to run well, and i don't think heart problems run through my family. I used to not excersise as much except for saturdays at Tae-Kwon-Do for 2 or 3 hours. But, i am have been starting to excersise more. But sometimes, i feel this ache feeling in my chest. (It does not hurt, but it is not comfortable.) Sometimes i also get this feeling like it is a little hard to breath, and i have to breath much deeper. I felt that feeling yesterday. I was going to a party and was talking to my dad, i got kind of nervous about something, i felt the uncomfortable ache feeling in my chest, then for a little bit it felt a little hard to breath but it was better after. After the party, i thought i was just muscle tightness due to the fact that my shoulder and back also felt kind of tight. So, i woke up and i didn't feel any of those things. But, i did feel slight ache feeling in my chest again for a while. (Only that and it is kind of on and off.) Also, this usually does not happen but only once in a while. Is there something wrong with my heart? Thanks!:)