What are the symptoms serous otitis media and what is it caused from?

Fluid in ear: Serous otitis media is simply fluid in the middle ear (behind the ear drum). It can be caused by allergies or viral infections. If fluid stays in this area, it may become infected and need to be treated, but the serous fluid usually clears up on its own. You may have a blocked feeling in your ears, feel pressure, or popping in your ears.