Is this teething pain? what else could it be?

My son is almost 2 years old.
He went to the dentist a few weeks ago and she said he had all his teeth except for 2. (or did she say "two more were coming in" ?)
It was tough for her to check because he was crying the whole time and my wife had to hold him down.

Recently DS will be normal (in a good mood laughing) then all of a sudden start screaming like he is in a lot of pain and he will start pulling at his lower lip/front lower middle teeth. Then about 20 seconds later he seemed to be over it. But then a little while later he would do it again.

I pulled his lower lip down and did not see any cuts there.

He's young enough that his lower middle teeth should not be rotten/root canal needed.

My friend said he could be teething (molars) and that he just pulled at the closest teeth.

But that sounds weird.
What else could it be?

Thanks

Is this teething pain? what else could it be?

My daughter always complains about mouth pain when she has an ear infection