Had one done on an eye tooth. The pain is very minimal. Most dentists will prescribe you Oxycontin for afterwards, too. Mine was sore for ~1 week, but it was a dull, easy to ignore, sore.
The one thing I would caution is the fallout of a root canal. Your tooth is now dead. You *WILL* have to have a crown done in the future. Not immediately by any means, but eventually. I had mine done ~3 years ago and it's starting to show discolor at the base just now, which I understand is common.
So, make sure you keep up that dental insurance so when you do have to get the crown you don't have to pay through the nose for it.