I know I'm not Bryanna, but I've had obscene amounts of dental work done.

Outside the fact anytime you have a root canal the tooth retains the infection, second time root canals have a much lower success rate. I'm missing 5 teeth (have implants) and 4 of those I attempted second root canals on and they all failed within a year. A dentist once explained that a root canal doesn't save a tooth, it just gives you more time until you lose the tooth. Root canalled teeth are incredibly brittle, so they break easily, and often times there is a crack in the root they can't see on an X-ray.

If you don't replace an extracted tooth, the other teeth usually shift to fill the space-unless it's a back molar, and the opposing teeth get longer because there is nothing to oppose it.

I don't know the answer on if the infection can cause the pain long term, but I would guess yes.