An ear infection occurs when a bacterial or viral infection affects the middle ear—the sections of your ear just behind the eardrum. Ear infections can be painful because of inflammation and fluid build up in the middle ear.
Ear infections can be chronic or acute. Acute ear infections are painful but short in duration. Chronic ear infections do not clear up, or they recur many times. Chronic ear infections can cause permanent damage to the middle and inner ear.
Ear infections occur when one of your Eustachian tubes becomes swollen or blocked and fluid builds up in your middle ear. Eustachian tubes are small tubes that run from each ear directly to the back of the throat.