I dont know if i have a heart murmur, but i have this thing called a MITRAL VALVE PROLAPSE where it beats funny sometimes... anway, the thing is, it only starts acting up when i'm stressed (not physically, but stressed from work) and not doing anything.. so if i'm stressed while lying down or sitting down then it starts feeling funny. But once i start getting my heart rate up by going up the stairs, biking, running, etc it goes away, and also never appeared in my treadmill test while pushing the limits, but it did when i was in resting mode. So yeah the doctor said i should be fine if i just keep exercising. Weird huh?