I have an umbilical hernia which is about the size of a large melon. I have had this for quite a long time, but recently I have been having pain on my right side radiating from the front to the back. I only have this pain when I am laying down and try to turn. I can turn either left or right and it is still there. It is so bad that it takes my breath completely away. I do not have this pain when standing. What could be causing the pain only when laying down?