I have a few ideas that might help. Cats will sometimes bite gently (called a love nip) and want to play with you. When you push your cat away, you are confusing him. Try distracting him with play using a stick with something on it instead. Also, check his teeth to see if there is something wrong with one of them. Bad teeth can be a problem for cats because they can't eat and it can poison their system. Another thing you can do is make sure he has scratch pads. I find the ones made out of cardboard are the ones they like best.