Just to be clear you are hearing your heart pound in your ear, or you have tinnitus (ringing) with a fast heart rate, or something else?
Generally speaking tinnitus is often not that related to the ear, so the ear usually checks out fine. Underlying anxiety disorders, thyroid conditions, hormonal changes/problems, sinus/allergy issues, cervical disc issues, etc. can be behind that.
If you general bloodwork checks out that more or less rules out thyroid and hormone problems. An MRI can be used to rule out a brain tumor (very unlikely without other symptoms).
Generally speaking the gamut of the potential underlying issues can be dealt with with acupuncture, so as this is a fairly new symptom, I would simply suggest you find an acupuncturist in your area and give them 6-10 treatments and I would suspect this would be gone in that time frame, particularly if you are otherwise generally healthy.