What Is It?
Pain in one or both ears can occur for many reasons, some not related to the ear at all. When the pain is caused by an ear problem, the most common reason is blockage of the passageway between the middle ear and the back of the throat. This passageway is called the Eustachian tube.
The middle ear is the small, air-filled cavity just behind the paper-thin eardrum. Normally, air enters the middle ear through the Eustachian tube, equalizing the pressure between the middle ear and outer ear. The Eustachian tube also drains fluid out of the middle ear. When this tube becomes blocked, and air and fluid cannot flow freely, pressure builds in the ear, causing pain.
If fluid behind the eardrum becomes infected with a virus or bacteria, it causes a middle ear infection that can lead to pain and fever.