What a Pain In the Root Canal !!!!

Ok... so i posted a topic about how my tooth hurt bad for several weeks after a root canal done by a regular dentist and now it's worse!... I went in a few days ago and saw an endodontist(a root canal specilaist) He ended up doing a second root canal and explained to me that there was another little nerve canal at the end of my root... So good news I thought.... 3 hours later i go back to the regular dentist to have my temp put on and I was in soooooo much pain I told them just to pull the tooth.... I'm not trying to be dramatic but this was the kind of pain that you think you'll never experience. He tried everything to try to numb me and nothing worked...
And by the end they talked me into keeping the tooth and told me that it was just irritated from the second root canal... and of course THAT IT WOULD GET BETTER!... He also mentioned to me that I'm not the kind of person who can have root canals... my body just rejects them... well nice, but not comforting... So the next day i went to another dentist for a second opinion and he told me something that the other two dentists that had been working on me forgot to mention... He said that the root canal looked like a very nice job and that sometimes the ligiment around the root can become irriated and feel just as sore and sharp as the nerve that they took out...
So is this true????
I sat there wondering why my other two dentists never thought that would be helpful information to someone thats telling them to pull the incredibly tooth cause the pain is soo ridiculous....
Anyway I know this was long winded but I hope it can help someone going through a similar experience...
Apparently root canals are not just simple procedures that go without a hitch>>>
It now been two days since my last root canal and i'm a grown man who is absoulutley dreading going to the dentist at 4 o'clock today...Stilll have some pain and not confident that it won't be worse by 5 o'clock : (
Good luck to all