Hmmm. One explanation could be partial pollination, but that's hard to believe if *most* of your apples are like this. Partially pollinated apples will not fill out on the side where the seeds aren't growing. Without a picture, the quality of responses you might get here will be lower.

Are there any worms in the apples? Coddling moth can make the apples quite deformed and scabby looking.

Frost damage?

Deformed apples are nearly always due to plum curculio. Codling moth comes later so usually does not deform them nearly as much.

Scott

apple scab... do you see any small black spots on them?