Whenever I buy cheap ice cream (i.e. Mac Donalds Soft Serve) or service station slurpies I almost always get a brain freeze when I consume it too fast, I know how to prevent getting these (slow down consumption) and I assume that it's caused by the temp. of the food/liquid I'm consuming, but what is the science behind it? Is it muscles or something contracting really hard and fast causing a cramp? And why do i predominately get it from the cheap stuff.

P.s. I’ve theorised that I don’t get it from more expensive ice cream because it tastes so good that I take my time and enjoy.