Eminem - "White America!" is a great music video. Please watch it. It is one of the few times I have seen flash used so well (admittedly, I don't get out much, though.)
The video "places the viewer in the body of Eminem as he moves through the media-drenched environment that is the subject for his critique of American society." More info on the making of the video at GNN.
When I was first learning photoshop, I would go to phong.com. That guy was one of the artists on the video.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.