My very active DS is 9 months old and screams the house down every single nappy change. He also screams when I put him in his car seat, and sometimes in the high chair. For a while I just thought he was overtired/hungry/just wanted to get down and crawl but now I am thinking there is some other issue. He is a very unsettled baby in general and I literally cringe when we go out places, just waiting for him to scream the place down. He has never been a great sleeper, especially at night. I've have seen a number of doctors. Anyone have any idea what if anything might be wrong with him?