Pain in the ear has many possible causes and may be accompanied by other symptoms.
The U.S. National Library of Medicine offers this list of possible reasons for earache:
Arthritis in the jaw.
An infection in the middle or outer ear.
Changes in pressure that damage the ear.
An object lodged in the ear, or a significant buildup of ear wax.
A ruptured or perforated eardrum.
A sinus infection, infected tooth or sore throat.
Temporomandibular joint syndrome (TMJ).