A rib strain can cause you pain with a deep breath, and forget about sneezing or coughing! It can also be tender to the touch, like a bruise, and you might even be able to notice that the rib feels twisted or out of place a bit.
There are definitely things you can do to speed along the recovery to this injury even if you’ve been told to just take it easy and wait it out. Stretches will help improve the circulation and loosen up the muscles, relieving your pain. If the tight muscles have tugged so hard that they cause the rib to twist, that should reverse itself when the muscles relax out of their tightened or spasmed state. Sometimes a physical therapist would manually try to mobilize it back into place, but relaxing the muscles is imperative to getting a full recovery.