Root canal then crown procedure completed. none days after permanent crown placement, my gum hurts (but only if tooth tapped). i can chew on the side with brown but tap tooth and gum sore. why please?

You can chew with that tooth so the root canal was successful then your problem is due to gingival inflammation either from gingivitis or irritation with poor crown fitting. You can apply oragel (teething gel) as often as needed for discomfort then call your dentist for further advice. Good luck!

There are a number of reasons for sensitivity on percussion. Have your treating dentist reexamine that tooth for potential causes, so hard to diagnose without more information.

You had surgery, both the tooth canal treatment and the crown preparation. Both required manipulation of soft tissue and reshaping of hard tissues. Prolonged sensitivity is not an uncommon sequelae. Please seek reexamination, resolution may be readily achieved.