The ice cream headache, often called a "brain freeze", is actually referred pain from the roof of the mouth which you feel coming from the temple area of your forehead when you suck cold beverages through a straw, sucking the liquid directly onto the palate. The drink doesn't get chance to warm up before it hits the roof of your mouth.
冰激凌頭疼，有時也叫“腦凍結”，指用吸管喝冷飲的時候，冷飲直接到達上顎時感覺到的來自太陽穴的疼痛感。冷飲在到達上顎之前沒有足夠的時間升溫。

There were simple ways of avoiding the problem in the first place when ordering your ice cold beverage.
在點冰凍飲料的時候其實有簡單的辦法可以避免這樣的問題。

The simplest way when you are drinking through a straw is not to angle the straw in the direction of your palette.
最簡單的辦法就是喝冷飲時吸管不要直接對著上顎。

Those who remember their manners and eat their ice creams slowly are much less likely to have a problem. (Source: telegraph.co.uk)
時刻注意言行、吃冰激凌也慢慢來的人也不太會遇到這個問題。