She had her tonsils and adnoids out one week ago. She acts good a lot, but she screams, hits, throws things, doesn't want to take her medicine. We see a severe change in her behavior. She has never acted like this before. We are very worried. Is this normal.

Yes and no. Sometimes having to go through a situation like that can caus trauma that may be temporary. At first you dote on her a lot and then you have to back off so there is sepration anxiety and other things going on. Give it time and keeps consistent boundries.