What causes headache no fever?

Many possibilities: Most people have a headache at some time, such as from colds and flus, lack of sleep, too much driving, long hours on the computer, stress at work, etc... Some people temporarily try Tylenol, Motrin, Aleve, Excedrin Migraine, or their generic brands for some relief. A bad or increasing headache, recurrent or weird headache, or one with other worrisome symptoms must be examined.