How long should aching pain last after crown?

Hi:Please have your dentist check your bite in all different jaw movements and check for any clenching or grinding habits.  This type of pain can last 4-6 weeks, otherwise you need a root canal.Best,Dr. Maddahi

Hello, 
Some post-operative sensitivity is common and normal.  It may simply be a question of your bite needing to be adjusted.  Sometimes the crown is hitting the opposing teeth earlier than the other teeth. It is also possible that there is excess cement around the margins of the crown, which may cause inflammation and discomfort.  Lastly, it is always possible that the tooth has a fracture in it that your dentist and the endodontist were unable to detect.  If you had pain during chewing, this could be the culprit, but you indicated that this is not the case.  I would start with the simple things first: check the bite and look for excess cement. 
I hope this helps!
Cheers,
-Miles