Hi, I just want to know if pulpectomy is charged separately from root canal treatment proposal or is included? I thought it was, until yesterday.

Dentist preference. They are separate dental codes so they can be charged per procedure. This is more of an individual dentist preference.
By whom? If insured by a dental insurance company, you would have to refer to the policy and definitions of that insurance company which may vary among insurance companies. A pulpectomy may be considered as a separate emergency procedure for the relief of pain or as part of a root canal therapy. Unfortunately it is often a gray area. The same goes for a private dentist and may be a matter of semantics.
Depends. Typically it can be the first emergency step in a root canal treatment. Most Endodontists would include this in the treatment, provided you follow-through in a timely fashion. Good Luck.