If you haven't had it very long, it might still be settling in. We have had several hamsters. We always leave them alone completely for several days when they first arrive from the pet shop (apart from feeding them of course). Then taming them is very gradual - tempting them into a tube, letting them run on a lap, getting them used to our smell etc. It would be 3 weeks or so before we'd attempt to pick one up. Even once tame, I don't usually pick them up straight from their cage but allow them to walk out onto a hand. If they sense a hand coming down onto them, they will be scared it's a bird or something coming to eat them and of course they'll bite. I know they're all domesticated now but instincts are still very strong. i would persevere, but take it slowly. Buy a good book to help - I recommend 'The Really useful Hamster Guide' or something like that. Good Luck