I am experiencing the exact same thing. It's terrible. I can't focus. I am irritable. My head definitly feel like it's going to explode. I went to a specialist and he doesn't see how the root canal can be related to these headaches. I have never had this pain until they worked on my tooth. It's very scary. It is effecting my work and personal life. I can't focus or pay attention. I am going to see my regular doctor this week to see what he thinks. I am very upset. It seems that the medical community doesn't think that they are correlated. We all know ourselves better than anyone- I only experienced such severe headaches the day after I left the dentist for my first rootcanal.
Jessica