Marlene
I have experienced two bouts of this condition.....VERY painful. Pain was from the sternum to the spine and lasted for several weeks. My doctor told me the cause was inflammation of the (can't think of the word right now) but it is the material that joins the ribs to the sternum and spine. He prescribed an antiinlammatory and it cleared it up in a couple of weeks. It sounds as though there can be more than one thing that can trigger it.