I get that occasionally, too, where my ears feel clogged, even though I don't have a cold or allergies going on. It usually clears up after a short while. I did have a weird thing about a month ago where my left ear felt really clogged, I was having a hard time hearing, and I had ringing in that ear. It was pretty annoying but it went away after about 3 days and hasn't happened since then. I don't know if it's related to stress, but it could be.