I agree with Prism and the others. I think
any activity where you are sitting in one position too long will result in pain. It's very easy to do with something like quilting because you can get so absorbed in what you're doing (or what you're watching while doing it
) that you lose track of time or don't think to get up and move. I get this way when I'm absorbed in a project at work and don't realize it until I get up to walk over to the printer.
Try to get up and walk around every 15 or 30 minutes. Stretch, drink some water, check the mailbox, whatever.