Puppies all go through a teething stage. They explore the world around them with their mouths. He not only will chew on you, but also anything he can get his little mouth on.
You will need to teach your puppy nice biting, or bite inhibition. Here is an article on bite inhibition:
http://www.shirleychong.com/keepers/archives/bite.txt
You will want to read this, it is very informative.
When your puppy begins biting you and he bites too hard, make a high pitched yelp or say "ouch" to mimic a dog yelping. If you have ever observed puppies playing together they will yelp if the other dog bites too hard. Then, the puppy that was bitten, will get up and walk away to end the play time. After you yelp or say "ouch", put the puppy down and walk away for a few minutes. He will soon learn how hard is too hard, and how hard is a nice bite. I hope this makes sense. The article on bite inhibition will be a help.
As for your puppy teething, put biter apple (it is a spray that you can get from the pet store) on everything that is on the puppies level. I've also read from other YT members that you can use clear deodorant and that it is suppose to last longer that bitter apple. It is worth a try! Hope this helps!