I had the same problem and still do. When I lay down, I have ribs on both sides that pop. After going to the doctors, she recommended that I have an x-ray
. The x-ray showed that those ribs that were popping out, were extra floating ribs. Normally, people are supposed to have 2 floating ribs on each side. Instead, I have 4 on each side. It just means that those ribs are not connected to the sternum by any cartilage.
Hope this helps!