I had a root canal and was in pain. I had an infection. After I started taking the Amoxicillian my dentist prescribed, the infection began to go away. To ease the pain, I took extra strength Tylenol and applied ice to the area. The nerve is gone after a root canal, so I don't believe you should be having much pain. I would contact my dentist!
Call your dentist before you do anything, this may have been an incomplete root canal. He can xray it and determine if there is any nerve left. The nerve is gone so you shouldn't be having any pain, maybe some soreness but no pain. Call your dentist and go from there. Take care and I hope you get some relief!