Omg me too!!! I’m unreasonably thrilled to find my weird bendy rib pain people.
Bending to deal with shoes or socks sometimes, and almost always when trying to pull off wetsuit boots or swim shoes.
So painful, and exactly as described, like a twist or a pop, suddenly feeling something is really not where it ought to be, so it kind of takes your breath away with the ouch.
Then it goes back somehow, but feels weird and vulnerable to happening again for a day or two.
I was scanned for hernia but nothing found, so told not to worry about it and just aim to avoid the movement that triggers it.
Right side for me, just under rib, and started when I was late forties.
I can’t tell you how good it is to know this is a thing.