I am having a hard time with an unexplained toothache. Do I need root canal treatment?

I started having a toothache in my lower right molar a few months ago. The pain mainly occurs when I chew food.

I went to the dentist for an examination, and they said they couldn't figure out the cause. They mentioned that unexplained toothaches like this occur occasionally and suggested that if it is really bothering me, we could try a root canal.

It is a toothache where even the dentist doesn't know the cause. In this case, is it appropriate to have a root canal?