Thanks so much you for your help.

No, thankfully, I do not have any other root canals in my mouth. I'm very happy I got the one that I did have removed.

Btw, I looked in the mirror right now and took a closer look. It almost looks like there is a little cut or divot where the missing tooth is and it extends towards the lining of the tooth next to it. The area seemed to heal nicely as it looks, but that thing that I'm seeing, maybe it's a cut or something? If it's possible for me to get a picture of it, can I post it here for your professional opinion?

The pain is very similar to what I was experiencing before, that's why I'm worried it's reinfected somehow.

With that meridian chart, I am unsure which numbered tooth correlates to which tooth in my mouth. I will see if I can figure it out and get back to you on which tooth it is that bothers me.