Is it normal to have a tooth prepped 3 weeks before a root canal when there wasn’t any pain to begin with?

Went to a new dentist last week, knew I had some decay and cavities but haven’t been in any pain thankfully. Was told I need 3 root canals based on x-rays and they were surprised I hadn’t been in pain yet. I had a ton of info thrown at me all at once, did a saliva test I’d never done before, etc. and in the state of overwhelm I guess I didn’t understand I was agreeing to having my teeth that needed root canals prepped and topped with temp crowns until the actual root canals at the end of the month.

Well, not shockingly, now I’m in excruciating pain. Because duh. It makes sense that shaving a tooth down and further exposing the decay and nerve would cause pain, even with a crown on top.

So my question is, is this a normal procedure? I’ve only ever gotten temp crowns after the root canal itself before the permanent crown. I paid up front so I don’t feel like I can go seek emergency care and their endodontist apparently only comes in a few times a month. Any suggestions?