My 5 year old son with cf woke up this morning with a low grade fever of 100 degrees. He then told me that it hurt on his left side when he breathes in. I am hoping that after his treatment it will feel better. But I am concerned as he has never had this complaint before. It is not stopping him from playing or eating and he hasn't mentioned it since this moring unless I ask him if it still hurts. Any ideas??