Mostly when doing physical activity and some times at random it feels like something out of a movie my heart all of a sudden will start beating really hard my body feels completely drained it's harder to move or even sit me head will feel heavy and it becomes hard to breathe the only thing that makes it stop is me laying down and not moving at all and even doing that can take up to 30m to an hour some times more I'm 22 and this had been happening for 5 years now