What Headache truly means. - for reference purpose

I decided to post the proper and authentic definition of headache mainly for reference purpose.
Sit calm and read.
What is a headache?
Headache is defined as a pain arising from the head or upper neck of the body. The pain originates from the tissues and structures that surround the brain because the brain itself has
no nerves that give rise to the sensation of pain (pain fibers). The periosteum that surrounds bones; muscles that encase the skull, sinuses, eyes, and ears; and meninges that cover the surface of the brain and spinal cord, arteries, veins, and nerves, all can become inflamed or irritated to cause the pain
of a headache. This pain may be a dull ache, sharp, throbbing, constant, mild, or intense.
Now you know.