The pain inside the left ear is mainly due to the following clinical conditions: 1. Inflammatory infections, such as acute otitis externa, acute otitis media, and acute tympanitis, which are common in children and also in adults. 2. Viral infections of the ear, such as ear pain caused by auricular herpes zoster virus infection, which is mainly due to viral invasion of the facial trigeminal nerve. 3. 3. Pain induced by something growing inside the ear, such as middle ear cancer, cholesteatoma of the external ear canal, or localized masses compressing the nerve in the ear canal. In some cases, no abnormality is found during ear examination. This may be caused by otalgia, which is related to factors such as fire, poor rest and emotional stress.