Why would listening to certain songs cause a tingling sensation starting at the back of head and around ears ending in forehead?

The tingling sensation you describe may be a result of a phenomenon known as autonomous sensory meridian response (ASMR). ASMR is a pleasurable tingling sensation that some people experience in response to certain stimuli, such as whispering, soft tapping, or certain musical sounds.

ASMR is thought to be caused by the activation of certain neural pathways in the brain that are involved in social bonding and reward. When someone experiences ASMR, their brain releases dopamine, a neurotransmitter that is associated with pleasure and well-being.

The tingling sensation associated with ASMR is often described as a "brain massage" and can be very relaxing. Some people use ASMR videos or recordings as a way to relieve stress or anxiety, or to improve sleep.

While ASMR is generally considered to be a harmless phenomenon, it is important to note that not everyone experiences it. If you do experience ASMR, it is likely that you are simply more sensitive to certain stimuli than others.