Do you know of any stretching exercises to ease back and/or neck pain?

I’m looking for some easy stretching exercises to help with back and/or neck pain. I know my back is sore because I’ve been spending so much time hunched over books, but there’s not a lot I can do about that. Essays have to be written, and though I try to sit straight in my chair, I’m a handwriter and I’m constantly referencing giant books, so my back inevitably gets stiff after working for a while.

Anyone have any ideas about how to stretch out my ouchies throughout the day and once I’ve called it a night?