A long time ago I bought a book called "how to live 365 days a year" by a Dr. Schindler. He explains how we can worry ourselves into aches and pains. I used that book as a bible for years and must have loaned it out as I couldn't find it so I bought another one.
It somehow makes me feel better when I read it and it's easily understood. You might be able to get it or request it from your library or just buy the paperback. It's well worth it.