Wojtek Midlards, who is an MD and an assistant professor at the head and neck surgery center at Johns Hopkins, adds that brain freeze is a type of referred pain where the physiological changes in one part of the body cause pain in another. This experience is so severe because this sudden dilation sends a pain signal through the trigerminal nerve extending into the mid face and forehead. The brain freeze sensation originates from the tiny muscles around the blood vessels in the palate, which are tightening and then relaxing