First off he is pretty young and most snakes in general are a bit high strung/defensive when their young. They have to be otherwise they'd get eaten in the wild.
He's probably swinging side to side because he doesn't feel secure. One method that I like to use is the "movie method." Pop in a movie, plop down in your favorite comfortable chair and set the snake in your lap. Don't move much, don't pet him, just sit there and enjoy your movie. Most likely he'll just sit there and do nothing. If he moves, don't restrain him...let him go where he wants (unless its inside the chair). It's calming, he has a firm, secure surface to lay on, and he can get used to your smell and temperature. Do this once or twice a week and you'll have a nice tame snake in no time!
Does it hurt when they bite you? A little, it may bleed a bit, but it's like a few pin pricks...not that bad. Personally, I hate getting bit, but you get used to it after a while. Just make sure if they do bite you to:
1. Not get mad and handle the snake roughly
2. Don't put him away...if you do he may do it more because he's getting what he wants.
3. Try not to be jumpy/nervous around him. This can be tough, but I think snakes can sense when someone is nervous by the way you move and this may encourage it to bite more.
Matt