Corgi puppy (16 weeks) will occasionally squeal bloody murder and pee everywhere

Sometimes, when the pup is running up the stairs or rough housing he will start squealing like he's dying and pee everywhere. I think he's pulling a muscle or something.

Vet said to keep him rested, not to let him run up the stairs, and not to let him rough house. Also said to give him baby aspirin.

Has anyone here dealt with this before? Anything else I can or should be doing?

Thanks