Pain at the root of the ear in the lower jaw can be trigeminal neuralgia, or it can be caused by mumps or mandibular adenitis. 1. Trigeminal neuralgia: the mandibular branch of the trigeminal nerve is distributed in the part of the mandibular cleft, and usually the innervated part of the nerve will have a knife-like pain, which will be manifested as pain at the root of the mandible. 2. Mumps: the cause of mumps, virus-induced early stage may be manifested as the root of the chin and ear area, parotid area pain, and later will gradually become a diffuse swelling centered on the earlobe, accompanied by elevated temperature. 3. Mandibular adenitis: occurs mostly for the gland secretion and duct obstruction induced by local inflammation, the cause of the occurrence of bacterial or viral causes, will be manifested as pain in the root of the ear of the jaw. Pain at the root of the mandibular ear may also be caused by other reasons, it is recommended to consult a doctor in a timely manner, complete the relevant examinations, clarify the causes, and follow the doctor’s instructions for treatment.