I have been able to hear my heartbeat in my right ear
As many people have already said, this phenomenon is quite common. I'm a little surprised, however, that it's not been said yet that it's largely dependent on the
type of flow in the large vessels near the business part of the ear.
I hoped I might be able to find a good anatomical diagram of the ear to post here, but I haven't so far. Suffice to say that on each side one of the large carotid arteries passes extremely close to the hearing mechanism on its way to supply the brain with oxygenated blood.
Blood flow in a healthy heart and in most healthy arteries is
laminar.
This means it does not generate sound. If there is a disruption to this for any reason at all the flow can become
turbulent. Often this type of flow generates sounds ( eg: it is how the doctor hears "
murmurs" with his stethoscope).
I agree with most of the reassurance that has been given here hitherto, but would advise an expert medical opinion to be safe, and especially if the OP is in middle-age or greater ! That is the age group in whom turbulent arterial flow due to atherosclerotic deposits would be most likely.