Before I took Alexander lessons, I never thought about the way I read books. I never thought about my sitting mechanics. I never thought about the strain of holding a book up.
Nuitsmani comments on one of my videos on how to sit: “When reading a book (or writing) I put my book (or journal) on the table. And so I need to bend my head down. Is it a right thing to do? Or should I bend from my hips while keeping my head aligned with my back?”
I would recommend putting the book or journal under some pillows on your lap. I use three pillows.
I also read standing up, allowing my book to rest on the back of my chair.