(Concern) My molar is throbbing and uncomfortable.

My lower left molar is aching. It feels especially sensitive when I drink cold beverages or eat cold foods, and chewing is a bit uncomfortable. I went to the dentist to get it coated and filled, but it still feels sensitive. I don't want to undergo root canal treatment, but are there others who have experienced the same? I had a scaling before the treatment. I am not using fluoride toothpaste, but I am curious if using fluoride toothpaste would help.