Pain is mandatory suffering is optional – The Mechanics
Pain is a function of the body, to guide you away from something not beneficial, like a hot stove. Keeping your hand on the stove will keep hurting. Once the body has been hurt, it will continue to hurt until you remove the source, and give it rest long enough to heal. That is not optional.
The pain of suffering guides your attention away from thinking that is painful and not beneficial. Keeping your attention on the pain will keep it hurting. Emotional pain stops the moment you move away from it, when you move toward something better feeling. That is optional. (Or just don’t even create it.)
Any feeling, thought, or belief …