History and exam
Everyone generally has at least one floating ribs some have a couple on each side though usually the lower ribs.
They can get irritated on your hip or on the ledge of a couch when you're leaning or a variety of other things. They are slow to heal. Sometimes you can feel them slip underneath another rib. That is uncomfortable. There's a lot of carlatun these ribs which is slow to heal. Even chest x-rays are not very helpful. Sometimes diagnostic nerve block can define things.