The pain in the left ear as soon as you eat may be caused by pharyngitis, inflammation of the temporomandibular joint, boils on the external auditory canal and so on. 1. Pharyngolaryngitis: when the patient suffers from acute tonsillitis, pharyngolaryngitis, epiglottitis, etc., in the process of swallowing, through the nerve reflexes, so that the left ear hurts when you eat something. 2. Inflammation of the temporomandibular joint: pain in the left ear when eating may be caused by inflammation of the temporomandibular joint, in the process of chewing, opening and closing the mouth, the activity of the joint will be stimulated, resulting in pain, and also cause pain and discomfort in the surrounding area. 3. Boil on the external auditory canal: the pain on the left side of the ear when the patient eats may also be caused by boil on the external auditory canal, due to the inflammation of the skin of the external auditory canal, resulting in localized redness and swelling, and the pain will be aggravated when the ear screen is pressed or the auricle is pulled. It is recommended that the patient actively go to the hospital, under the guidance of the doctor to improve the examination to clarify the diagnosis.