Do you sleep on your right side? It may be fluid (snot?)that flows through your eustachian tubes into your middle ear. A doctor should be able to look into your ear and see if it is infected. Chances are, it will drain out when your cold dries up, and you'll be fine. Try some Sudafed to dry your nose up, maybe then the ear will drain and stop filling up. Don't blow your nose so hard, and if it really freaks you out, try sleeping sitting up. All right, those last 2 suggestions are a bit Dogbert-esque, but I thought I'd throw them out anyhow.
Oh, yeah, what Timrhu said, too.
Disclaimer: I'm an engineer, not a doctor.