A very painful ear that hurts when you open your mouth may be related to diseases such as external auditory canal boil, otitis externa or temporomandibular arthritis. 1. External auditory canal boil: It is a limited purulent inflammation of the hair follicles or sebaceous glands in the skin of the external auditory canal, which occurs in the cartilaginous part of the external auditory canal. It has severe ear pain in the early stage of the ear, which is aggravated by opening the mouth and chewing, and radiates to the same side of the head. 2. Otitis externa: it can be triggered by water in the external auditory canal or long-term stimulation of suppurative otitis media, which manifests as ear pain, burning sensation, secretion in the ear, and pain caused by pulling on the ear when opening the mouth. 3. Temporomandibular arthritis: the disease can be caused by malocclusion or muscular imbalance, etc. Pain in the joint between the ear and the jaw can be accompanied by ear pain, headache, etc., and there is pain when opening the mouth (mouth) or chewing. When the symptoms of persistent pain in the ear, you need to go to the hospital specialist in time, after clarifying the cause of the disease, and follow the doctor’s instructions for standardized treatment.