So, sounds like things are going well, on the whole? He's getting plenty of milk and growing very well, so that's good.
There are a few possibilities as to why he's doing this. It might be that he's finished feeding after a few minutes. What happens if you just stop the feed?
If he's biting, he must be pulling back and detatching from the breast. If you watch him carefully, you'll probably see when he's about to do it, and can pop him off quickly before he actually bites you.
The pulling and crying at the breast could be that he's trying to hurry another let-down along.

You might find it helpful to have a chat with an ABA counsellor for some more ideas and suggestions - 1800-686-268