Cluster headaches are severe pain attacks located on one side of the head and behind the eye. The headache comes in periods or so-called "clusters" of intense pain, and can last for periods from days to weeks.
Fever is very common, but is not considered a disease in itself. Despite the fact that elevated body temperature in the form of fever is a natural part of the body's defense against infections, in some cases it may be necessary to treat.
The vast majority of people experience headaches from time to time. Stress, little sleep, little food or too much alcohol can trigger the headache, and most often it helps to give the body rest and calmness.