I have a 5 year old (non-CAH) who gets pains in his legs, usually behind the knees and most frequently at night. I recently asked his ped if this was "growing pains". She said probably but also checked out his feet. He has high arches which she said can also cause pain, esp. if he has been running around alot that day. We have found if he rests with a pillow under his knees it seems to help as does simple massage. every once in ahile he has really complained and we've given him some tylenol. There are special inserts for shoes to help with the arch thing but since this is not a nightly thing we haven't dealt with it that way.