Sensitive tooth after crown and root canal, how do i take care of this?

Discuss with dentist: Speak to the dentist who treated you. He\she knows best what you should or should not feel, how long to resolve and whether or not you need to be seen again to evaluate the cause of your sensitivity. Lot's of possibilities in these type of cases. It could be as simple as adjusting the bite.

Call doctor: Was the root canal done recently and then the crown done very soon after? Was the tooth sensitive before the crown was placed on the tooth? Is the tooth only sensitive after the crown was placed? If it's the latter, then maybe the crown needs to be adjusted to settle into your bite. If it's any of the others, you need to contact the dentist who did the root canal and crown and get it looked at.