I got my favorite putting thought, which always loosens me up, from (I think) John Maynard Keynes: "In the long run, we're all dead."
Try it! Knocks the tension right out of a body.
Might work on full shots, too, for you. (When I try it, to loosen my upper body, I tend to loosen my grip, too, to such an extent that I'm lucky to hang on to the club!)
One other suggestion: Throw a bunch of clubs out of your bag. It's always more fun to play with fewer -- and kinder to your body, too.