There are many possible causes for patients to experience the feeling of a little stuffiness in the left ear, including water in the ear, secretory otitis media, and sudden deafness, as follows: 1. Water in the ear: Patients may have water in their ears from washing their hair, bathing, or swimming, causing the feeling of stuffiness in the left ear. Some patients are more likely to have this symptom if the ear canal is narrower and there are cerumen masses blocked in the ear canal. The cerumen absorbs water and expands easily, causing serious blockage of the ear canal and aggravating the feeling of stuffiness. 2. Secretory otitis media: Some patients may have upper respiratory tract infections that cause secretory otitis media, which can cause the symptoms of stuffiness and blockage. 3. Sudden deafness: Some patients may have sudden deafness. The condition may also cause similar symptoms. If a patient experiences persistent congestion in the left ear, further detailed examination is needed to clarify the cause.