Pain in chest/ribs after pull ups

[VinceField]

Started my session for back yesterday with a set of pull ups (didn't stretch) and felt a sharp pain in my ribs at the bottom and in the middle my left chest. It went away after a minute of stretching but since then i get a stabbing or sharp cramping pain in that area when I laugh, blow out air as if to see my breath on a cold day (pain comes when the breath is almost exhausted) and when I lay on my left side.

My guess is a muscle pull but I'm curious if anyone else has experienced this, what you did to promote healing and how long it took for the pain to go away.