I've got a really thick textbook I'm trying to read, but I've got a
bad back, and I've had some shoulder problems in the past, and
hunching over the book seems to be irritating them. It's too heavy to
hold up in front of my face for long periods. I've tried reading at a
table, reading with the book in my lap, and reading laying on the
floor. I always end up in pain. Any ideas on how I can read my book
without killing myself? I like to do a lot of highlighting in the
book, which makes it even harder to find a comfortable way of reading
it.

gremlin..

Hello once again!  The strain on your neck and back may very well be
due to incorrect posture while reading.  First of all, laying on the
floor is the worst posture you can assume while reading.  The most
ergonomically correct way to relieve the stress on your neck and
shoulders is to place the book on a bookstand that is at an angle. 
Interestingly, this correct posture had been around for a long time. 
An article in a 1923 issue of Popular Mechanics had a plan for the
Levenger Reading Table.  You can see it at
http://popularmechanics.com/science/time_machine/2002/2/ergonomic_reading_table/

Thanks for your question and I hope the above information is helpful
and takes some of that strain of of your neck.

Regards,

-THV

Search Strategy:
ergonomically correct book reading posture

References:

ErgoBoy
http://www.ergoboy.com/ergo_for/reading.php

ErgoDesk
http://www.ergodesk.com/overview.htm

Stern Chiropractice Newsletter
http://www.sternchiro.com/newsletter_0502_posture.htm