Conditions Possible mites?

My pig acts a bit weird sometimes. I've been reading around about pigs that tend to bite when being held, and quite a few people say it might be because he has mites. Sometimes when I'm petting him and sort of stares at my hands and tries to bite them, and he's already taken a few good bites out of my fingers. I tend to pet him around his lower back / bum area because I love hearing him purr and he sorts of twitches his legs and raises them all funny. He also absolutely hates being picked up. No matter how I try to pick him up he's either bitting me or just trying to get away. So if I'm holding him in my hand, support all four of his feet and nipping at me, so I often have to hold him by his sides which I hate because I don't know if I'm hurting him, and then his legs are just going crazy because he wants down. He also tends to jump out of my hands and hit the bottom of the cage and I think he's going to end up hurting himself! Do you think he just isn't used to being held, or should I possibly have him checked out?