As Devon Diver mentioned, Swimmers' ear is in the outer part of the ear and is like an inflammation. If you pull on your pinna (part of ear that protrudes from head), and you have swimmer's ear, it will often cause the outer ear canal to hurt. "Ear beer" after diving can help to prevent this.
But, since you were in a pool, and because of the "stuffiness," I would guess you have something going on in your middle ear, as DevonDiver described. This won't be helped by ear beer or by putting medicine in your outer ear now. It would likely have been caused by something you did while equalizing (or not equalizing). I've also given myself middle ear trouble (similar symptoms) by blowing my nose really hard when I had a cold (with other nostril pinched shut). The fluid in my middle ear took a long time to go away so I don't do that anymore!
One equalizing tip that *really* helped me (I used to have major challenges equalizing) came from SB: "Equalize" your ears on the surface, before you put your head into the water. This "pre-puffs" your eustachian tubes and makes it easier to keep on equalizing as you descend (just don't get too far "behind," as DevonDiver mentioned). My diving was totally changed for the better after I got this tip.