If you have had pain since the root canal, there is a chance that an error occurred during the procedure. If the pain is recent, you may have a cavity.
The many have a problem in your jaw where the tooth was drilled and the filled. The crown could also be displaced or missing allowing air and food to get in and cause pain.
The pains you have after a root canal may be due to infections only. The sweats which gathers
in the head would make such type of infections. See if its bulged in the paining place. Take
tablets for infections. If its not cured take pain releiver tablets.