I read somewhere that certain kinds of cancer can move from one side of the body to the other. I can feel things that bother me for a few days on one side of my body, and then switch to the other side. There are other things that cycled and keep coming back in the same spot over and over. Right now there is a red crusty itchy burning spot thing under my right eye. Seems like the battle is often a two steps forward, one step back journey. And you don't quickly start marching forward again, it will be a big down hill slide to misery and death.