Pain behind the ear is considered to be caused by auricular trauma, middle ear mastoiditis, boils and other diseases. 1. Trauma behind the ear: If there is a history of trauma, the local soft tissues are injured by external force, which will cause swelling and pain, thus leading to pain behind the ear. 2. Otitis media: Otitis media is an inflammation that occurs in the middle ear, the cause of which is related to pathogen infection and dysfunction of the Eustachian tube, etc. Pain behind the ear can occur when the mastoid is affected by the prolonged development of the disease. 3. Boil: Boil is an acute purulent inflammation of the hair follicle and its deep surrounding tissues, the cause of which is mainly related to infection, commonly Staphylococcus aureus. Boils can occur in any part of the body, commonly on the head, face, neck, and in some patients, behind the ears, where the patient will have localized red nodules, about the size of a pea, with significant pain. There are many causes of pain behind the ears, and patients are advised to visit the hospital for a definitive diagnosis.