Tooth pain

Ashlyn
For any hygienists, dentists or dental assistants...I could use your opinion. I have had sensitivity to heat in a very specific spot for a couple weeks now. Only to heat, no pressure or cold sensitivity. I've been to the dentist twice now. No cavity. He has redone two fillings trying to fix the problem bc I don't have any new cavities that need to be filled. It's only been 1 day since the last procedure, but I am still having that sensitivity this morning. It's not a constant pain, it only hurts when I eat or drink hot food, feels like nerve pain. Goes away fast, but sometimes it lingers. Does this mean I need a root canal? Any insight? Thank you!