Fixations can occur at the site where the ribs attach to the spine, in other words, the rib is gliding in the joint like it should to allow for pain free movement. This can often occur by a forceful sneeze during heavy lifting or athletic activity. It feels like a stabbing pain in the upper back/rib area making breathing difficult.
A rib fracture is a broken bone caused by trauma to the rib area possibly from a fall or car accident. This is quite painful and makes breathing very difficult.