When i lay on my side a certain way my rib cage overlaps, you can actually hear this happening with a popping noise. is this normal?

It can be: If you have inflamation of the cartilage that connects the sternum or breastbone to the ribs. Or you might have a fracture, but usually these things are very painful. You are still growing, so that might be your explanation. If you are having pain, or it's sufficiently bothersome, seeing your family doctor would be the best way to find out what the problem is and how to deal with it. Best wishes!