Periodically it feels like my chest is vibrating/rattling and my heart beat speeds up and beats very hard and shortness of breath. no pain.

ATRIAL FIBRILLATION?: IT LOOKS LIKE PALPITATION SECONDARY TO WHAT WE CALL YOUTH WEEKEND SYNDROME . BECAUSE IT HAPPENS FREQUENTLY IN YOUNG PEOPLE WHO DON'T SLEEP WELL, DRINK TOO MUCH CAFFEINE OR UNDER STRESS. I SUGGEST SEEING MD TO DO EKG . IF IT BECOMES CHRONIC , YOU NEED TO BE TAKING BLOOD THINNERS. SOME TIMES WE CAN CONVERT IT TO NORMAL RHYTHM BEFORE IT FORMS A CLOT . IT ALSO COULD BE SVT);THIS REQUIRES CARDIOLOGIST