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.
冰激凌头疼，有时也叫“脑冻结”，指用吸管喝冷饮的时候，冷饮直接到达上颚时感觉到的来自太阳穴的疼痛感。冷饮在到达上颚之前没有足够的时间升温。

There were simple ways of avoiding the problem in the first place when ordering your ice cold beverage.
在点冰冻饮料的时候其实有简单的办法可以避免这样的问题。

The simplest way when you are drinking through a straw is not to angle the straw in the direction of your palette.
最简单的办法就是喝冷饮时吸管不要直接对着上颚。

Those who remember their manners and eat their ice creams slowly are much less likely to have a problem. (Source: telegraph.co.uk)
时刻注意言行、吃冰激凌也慢慢来的人也不太会遇到这个问题。