I broke a rib in a car accident once, the advice is general just wait it out. I also know a girl who's see wee she broke on sneezing
The worst thing is to have ribs rotated. I did this to 3 ribs at once and I'm
still receiving treatment for it (it's been nearly 2 years since it happened). Basically ribs flex up and down to allow movement and breathing and I had 3 of them trapped in a rotated position, which hurt like a bandit, and was causing all the muscles in the area to swell up and go nuts. To fix this a physio needs to basically poke the affected ribs hard enough to shake them lose from their position and let them fall back into place, which takes a lot longer than you'd think. They'd been rotated so long they were starting to stick there
