Pain after Internal Bleaching?

Two days ago, I got my front tooth internally bleached (it has been root canalled already). There was no pain during the procedure, but about 20 minutes after, I got a pulsating pain coming from inside the tooth. I took a few Ibproufens and that did help a bit. Now, the tooth is tender to touch, and strangely it only hurts when I excersize, and brush my teeth, or when i'm trying to fall asleep. Please help.