This is serious : ) I've been in PT, and I swear it's had the side effect of helping me figure out how to study w/o pain.
1) Take breaks -I was told every 15 min, but honestly, that's hard to do, I try to stretch every 30min.
2) Work out those upper back muscles. Do push ups (or wall push-ups, if you're somewhere where touching the floor would be either gross or awkward) -make your scapulae get close together. Make sure you're incorporating those muscles in your workout routine.
3) Work at a whiteboard if writing, or take over a video projector if using a computer -at home our tv is a computer, so I can do class stuff on a big tv screen standing up, but at school, just hunt for an empty classroom to take over.
4) prop your book or laptop w/ a pillow so you're not scrunching forward to look at it.
FYI, the elementary kids in my neighborhood have those new smartboards in their classrooms and their teachers let them use them. I'm jealous. Freakin' public school 3rd graders have cooler stuff than me.