Headache
A headache is a condition of mild to severe pain in the head; sometimes upper back or neck pain may also be interpreted as a headache.
Headaches have a wide variety of causes, ranging from eyestrain to inflammation of the sinus cavities to life-threatening conditions such as encephalitis, brain cancer, meningitis, and cerebral aneurysms. When the headache occurs in conjunction with a head injury the cause is usually quite evident; however, many causes of headaches are more elusive. The most common type of headache is a tension headache. Some people experience headaches when they are hungry or dehydrated.
It is common to take over-the-counter painkillers such as aspirin or acetaminophen (sold as Tylenol or Panadol) to relieve headaches.