A sinus infection, also known as acute sinusitis, happens when your nasal cavities become swollen and inflamed. Ear pain can result from pressure build up. Treating your sinus infection will ease your ear pain. Sinusitis is often caused by colds and allergies but can also be a result of other medical conditions.

It isn’t unusual to find fluid in the human ear. This condition, known as serous otitis media, is relatively common in children, particularly those who are exposed to second-hand smoke, who are recovering from ear infections or who have allergies or colds.