There are a number of expressions in English that involve the noun "head," among them ones like the headline above, "to give someone a heads up," or "out of their head." Most phrases like this can't be translated into German directly, and the slang or idiomatic phrases in German that use der Kopf are not directly translatable to English either.
Ach, mach dir keinen Kopf, Lothar. Du kannst ja gar nichts dafür.
Oh, don't make yourself a head, Lothar. You can't do anything about it.
Caption 36, Großstadtrevier: Neben der Spur
Warum machst du dir einen Kopf?
Why do you make yourself such a head?
Caption 1, Mark Forster: Chöre
It's a bit difficult in a literal translation to understand what is meant by sich keinen Kopf machen, but luckily the Yabla videos also clarify the meaning: The Großstadtrevier video states "slang, don't worry," and the Mark Förster video states "idiom, why do you worry so much?"
Wann finde ich endlich die Zeit, meinen Kopf freizubekommen?
When will I finally find the time to get my head free?
This doesn't mean that your head is literally stuck in something, but rather that you want to find the time to "clear your mind." Another variation is den Kopf freimachen.
Although we all know the English expression "to lose your head," it's usually a figure of speech meaning somebody is becoming irrational.
Wir machen ihn einen Kopf kürzer.
We'll make him a head shorter.
This expression, like the origin of the English expression, could mean to execute somebody by lopping off their head, but einen Kopf kürzer machen is usually used figuratively to mean that you will reprimand somebody or "teach them a lesson."
Go to Yabla German and search for the term Kopf and see the various ways such expressions are used.