two questions (root canal, crown ones)

hi guys, i got a root canal almost two months ago.

Fist questions:

My toot with the root canal can still feel like, sensitivity (when i brush my teeth or run my tongue over the tooth) in certain spots. My bite doesn’t feel off or anything, is that normal? It was like that since i got it i just thought it might go away. Maybe relevant but my wisdom teeth are growing in still. I smoke. 22 y/o

second: is there a time limit to get a crown? I have a permanent filling, and the orthodontist said he’d recommend i get a crown but idk if that means I HAVE to get one or not. i haven’t had the time off work to be able to stop by the dentist because i work full time. (The one we have here takes walk ins only. Never appointments. I don’t know why but that’s just how they do it)