What is the the most comfortable position to read in?

I like to read for long stretches of time, 2–3 hours or so. If I lay on my stomach and put a pillow under my chest my right shoulder starts to cramp. Sitting in a hard, straight back chair hurts my neck and makes my butt numb. If I recline on the chaise my lower back starts to hurt.

Does this happen to you? Have you found the “sweet spot” for reading? Or is my age starting to catch up with me?