Blockage of the left ear with a little pain when opening the mouth may be triggered by cerumen impaction, acute suppurative otitis media, acute diffuse otitis externa. 1. Cerumen impaction: The left ear is blocked with more cerumen, which may cause ear swelling and pain, and the pain is aggravated when opening the mouth, accompanied by tinnitus, hearing loss and other symptoms. 2. Acute suppurative otitis media: local tissue congestion and edema due to inflammatory reaction causes blockage of the left ear, and a little pain may occur when the neighboring tissues are stimulated by activities such as opening the mouth, swallowing, coughing and sneezing. 3. Acute diffuse otitis externa: inflammatory swelling of the external auditory canal can lead to blockage of the external auditory canal, pain, burning sensation and other discomforts, or there may be a little pain when opening the mouth. Left ear blockage, a little pain in the mouth, there may be other reasons, it is recommended to consult a doctor in a timely manner to identify the cause of early treatment.