Why do your ears pop or plug up after a head cold?

Eustachian tube. When you get a head cold, you get inflammation in your upper airways. This includes in the back of the nose. This is where the eustachian tube (et) empties out - the tube you usually use to pop your ears. With a cold, you can get fluid behind the ear drum which can't drain out through an inflamed et. Even without frank fluid, you can get abnormal pressure behind the drum that can't normalize.
Ears popping. The reason for the popping is that pressure builds up in the inner ear because there is inflammation around the eustacian tube. The eustacian tube helps let pressure out. Fluid build-up may also be contributing. Decongestants can help.

Related Questions

Tinnitus/plugged right ear after a common cold/ear infection. Used ear drops to help with pain. Now I cant pop my one ear and its ringinh. Ideas?

Ear infection. Ear infection is effected sinus not draining and generally relieved with antihistamine and or sudaphed.
You should see DR. Please visit your Dr. Immediately; It occured because your Eustachian tube is obstructed either by an allergy, an infection, a virus or sometimes a change in shape or function. Often this will follow a cold or throat infection, but can also occur in isolation. Those are the most common • Painful pressure • Hearing reduced, • Tinnitus • Fever and discharge from the ear. Throat pain.