What could be causing my intense eye pain?

Many causes!: Abrasion, acute glaucoma, iritis, infection, foreign body etc. Get checked out very quickly to determine the cause.

Too many to list: Intermittent or constant? Red eye or not? Could be abrasion, scleritis, iritis, glaucoma attack; see your eye md asap.

Several things: Intense eye pain can be from angle closure glaucoma (associated with loss of vision), scleritis (very red eye), corneal ulcers (from contact lenses or trauma), iritis (worse in sunlight) and several other things. These are all serious problems and you should go to the er if you have this.