Wegen der Hitze bekomme ich bestimmt Kopfschmerzen.
Because of the heat I will certainly get a headache.
Note
The article is part of the word: der Kopfschmerz. That way you learn the gender with it.
Remember der Kopfschmerz for good. ripiti brings the word back just before you forget it, with these sentences. Free, no account needed, works offline.