Floating Rib Dislocated, Tenderness, Movable Lump. What Could It Be?

I went to the doctor a while ago because my floating rib was out of place. He said it should get better over time and that I should do excersises to fix it and that it should get better over time. But it has not be en getting better, its been getting worse. The rib seems to stick out more than my other side and is tender at the tip of it. Iton the tip it has a little lump that moves around. It is very discomforting and irritating. I figure that lump is why the rip is longer than my other floating rib on the other side of my rib cage. Could you please tell me what this could possibly be and if it concerns any medical attention?