According to your description of orthodontics, the doctor said that four teeth should be pulled out. Your situation is that the dentition is crowded and there is not enough room for correction, so you usually pull out individual teeth. The tooth usually extracted is the first premolar.

Suggestion:

It is recommended to eliminate the tension. If your tooth is the first premolar with decayed nerve, this is the best and you can consider pulling it out. If it is other teeth, especially the first and second molars, it can't be pulled out.