That is a symtom of heart disease so you may have this if you are a smoker but a little chance and you maybe just be un-fit...do more exercise...or you may just have to much caffine in your body. I got worried I had a heart diease because my heart did the same beat fast for no reason but don't go thinking that cause of that I am now a hypocodriact that means you think you are ill but your not.
Hope This Works
If None Do Go See A Doctor :D
Hope This Works
If None Do Go See A Doctor :D