Well there are different kinds of headaches and each of them is caused by different but similar reasons.
We have
Tension headaches
They are relatively harmless and are usually caused by stress or as a side effect of an illness of malaria
Sinus headaches
This occurs as a result of the inflammation of the sinus. This then causes pain in the forehead and the area just behind the cheekbones
Cluster headaches
This is a type of a headache that's characterized by a circular pain around one side of the face as well as nasal congestion or running nose and watery eyes.
It has no cure and scientists believe that cluster headaches might be genetic