I have the same problem. My question is what is the solution? I had my root canal done. Within 2 weeks I started getting pain due to heat and cold. The dentist referred me to an Endodentist and said your problem is there is one more canal that is not treated. I went back to the dentist and he cleaned everything and said there was no one more canal and could not find any nerve. He put some chemical and he said it will kill the ends of the auxiliary nerves that come into the tooth that cannot be seen. Now it continues to pain. So I may need to go to the endodontist.
Question: What is he going to do? Look at the CAT image and then what? Will he ampute one of the canals of the tooth?

The endodontist should be able to get to the root of the problem (sorry, had to say it! :))
He/she should be able to figure it out. The tip of the roots may have to be surgically removed and filled.