I Feel My Heartbeat Hard Towards The End Of Exhaling.

I feel my heartbeat hard towards the end of exhaling. Heart beat stays at normal pace. I haven't taken any medication. Not on any medication. No new foods. I get about 7-5 hours of sleep constantly working. I have no idea what this is or what it means. I don't think there is any family history of heart problems. Any information would be greatly appreciated. Thank you in advance Tim