In 2011 had decay on molar under crown so root canal/crown. now tender submand gland + 4 gum on that side, tooth sore after grinding. whom do i see?

Dentist: See your dentist for a comprehensive diagnosis of the area.There may be other problems in the area , other teeth or gums.

Your dentist: The tooth may be re-infected, or you might have periodontal problems, or it may be another tooth. Hard to tell without an examination.

See your dentist.: Visit your dentist. He/she will take an x-ray and let you know the next step, be it something then and there or a visit to the endodontist.