I just went in for a routine checkup myself, and found out I had a heart murmur. He told me not to worry, but it freaked me out something terrible. I had to go in for an echocardiogram last week. The tech even told me not to be concerned, but Im still very anxious - my next appointment isnt until oct.8th.
Just dont obcess over it. There is nothing you can do about it, and chances are its not serious.