Why do i get headaches after a root canal?

Tension likely: I would wager a bet that most people experience some degree of tension during such procedures, which can lead to headache.

I have had : Several patients over the years report headaches after root canals & other dental procedures. In most cases the headaches were in the temporal areas and related to muscles. Longer dental procedures that require you to have your mouth open for several minutes can cause muscle pain in these areas. Of course there could be many other reasons. Please report this to your dentist and also to your PCP.

Root Canal Headache: can be very painful and may deprive you of your sleep. The cause is a flawed root canal therapy, or any new root canal infection. The treatment is antibiotics, pain killers and root canal re-treatment.

Several reasons: most common cause is from opening wide for a long period of time. The muscles constrict vessels causing headaches. Also the adrenalin in local anesthetic can cause headaches.