Do you have to go to an endodontist instead of a dentist if you want your root canal?

Maybe not. Many general dentists are able to do excellent root canals with experience. Difficult cases are better treated by an endodontist as they have high resolution microscopes that most general dentists do not. I have been practicing dentistry as a general dentist for 26 years and have treated over 1500 endodontic cases with excellent results. That said i refer cases to endodntists that are difficult.
No. Many general dentists perform root canals on a daily basis. However, if a general dentist does not feel comfortable, or prefers not to perform the root canals, they will refer you to the endodontist (root canal specialist). Please consult your dentist for his/her preferences.
Either. This all depends on the complexity of the root canal treatment and the skill, judgement and experience of the general dentist performing the procedure. A general dentist can do these procedures if they have continued extensive training in endodontics and have developed the skill and judgement over time.
Endodontist. No, your general dentist can perform root canals if he is comfortable doing so. Difficult cases are often referred to specialist.