It sounds like your kitten was feral before you got him. I have one that was like that too. Most of the fear behavior will go away over time once he learns to trust you, especially since he was young when he was found, but some things might remain forever. For instance, Pie will run away and hide whenever another person comes over, even if they have come over to my place a million times. She will hide until they leave, even if it is ten hours later. (My friends and I tend to do a lot of series marathons at my place.)
Pie will also occasionally get overstimulated when being petted, and will get cranky and may bite, but she always gives a warning. She also refuses to be held, and god help me if I have to pill her or clip her claws. She acts like she is being boiled in oil. The trip to the vet is certainly an interesting experience, too. But for the most part, she is a totally affectionate cat who loves me to death and is quite clearly in charge of the household.
Kittens tend to bite and chew on their owners, and that needs to be trained. Repetition and reinforcement are the key. Pie is definitely better than she used to be. First, no rough play that encourages biting your hands, even if you use one of those kitty toy mitts. The cat will make the association that it's okay to bite you. When the cat bites you, you should say "ow!" somewhat loud (even if it doesn't hurt.) as opposed to "no"! Mainly because the sound for "ow" tends to distract them easier than "no" does, because it is more surprising. (Trust me, I have tried both.) Immediately stop interacting with the cat, and ignore them for a while. (At least five minutes.) I don't know why specifically this helps, but it does.
