When I touch a spot on the lower part of my neck above my collarbone, I feel a strange vibration that's very noticable. It's not my heartbeat. What could it be?

Thrill. This sounds like you are describing a thrill which may be due to a strong heart murmur or other arterial abnormality. Further evaluation by your medical doctor may be required and may consist of either an echocardiogram or arterial ultrasound.
Thrill. This sounds like you are describing a thrill which may be due to a strong heart murmur or other arterial abnormality. Further evaluation by your medical doctor may be required and may consist of either an echocardiogram or arterial ultrasound.
A thrill. This vibration is called a "thrill" and usually indicates a connection, or fistula, between an artery and a vein. There are many arteries and veins in the region you describe. See your doctor- this is not a normal finding and should be diagnosed.