"A feeling of fullness" is how it has been described by ENTs sometimes. Not that it helps any.
My neurotologist said that it is not due to temporary closing of the eustachian tube, which is what happens in airplanes. That is relieved by yawning or chewing gum, actions that tend to open the tube again so the pressure can equalize. (This was after 3 months of all sorts of meds and nasal sprays attempting to unblock it before I was finally diagnosed, of course).
In fact he said it may be due to a reverse effect, where the hearing is muffled by some mischief the AN is up to, pressing on the nerve or artery for instance. The ear is tuned to detect slight changes in hearing, and may "interpret" them as a change in pressure, signaling your brain to try yawning or jaw wiggles in an effort to clear it. Any sort of inflammation around the hearing organs can probably produce this effect.
I don't know if I really buy it, but that was the gist of his explanation. It sure feels like pressure to me.
Steve