Why do I hear my heartbeat in my ears? Should I be worried?

No. This is pulsitile tinnitus. This could be normal. Your carotid artery as it enters the skull runs in very close proximity to the cochlea (inner ear). If you have never heard it before... See your local ent. This could be a sign of new onset high blood pressure. Some benign tumors of the ear can present this way as well.