[Ladylavender]

I think if your dog is coughing and choking a lot, it could still be his trachea. It may not be at the level were the voice box is. The collapse could be lower into the chest where it cannot be manipulated so as to encourage the cough to get a true diagnosis. Having said that if it is not causing him to pass out and he it is not causing him any physical distress than there is not much they can do about it. if it gets worse they can give him pills to help him breathe or do surgery.

As far as the biting, I believe what is going on here is fear aggression. Dogs will nip and bite when they are fearful. There are a lot of articles off the internet you can read about fear aggression. I don't think that putting him in a crate will stop the behavior.

I don't buy that your dog "knows" he is doing something wrong, otherwise he would not be doing the behavior. He is not connecting the punishment with the behavior. That may be why he runs and hides. He knows that he gets punished (not why) and runs to avoid it. The whole thing may be stressing him out.

Please reassess your disciplining techniques and read on how you can help your little one over the fear aggression. His is not to be blamed. He is only protecting himself.