Root canal through the crown or new crown?

I had a crown placed on a molar two years ago (painful st the time) & I have pain under it. The dentist just adjusted my bite. She did an x-ray, tapped on my tooth, and put cold air on it. She thought there was no infection. She said if I need a root canal, she will send me to a specialist to drill a hole in my crown to do a root canal. This seems more expensive than the dentist just removing the crown, doing a root canal, & replacing the crown completely. Is the latter an option in these cases?