Is this headache related to TMJ?

I know exactly how you feel! I get this too - it aches in that spot and also feels a bit tight I guess is a way of describing it, and then it seems to radiate around the sides of my head in a bit of a line. I'm also fed up with my dentist, as I have had TMJ for a while, but only recently got it diagnosed. I know it is connected to the surgical removal of my impacted wisdom teeth a few years ago, but he refuses to admit that and thinks it's because I grind my teeth - which I know for a fact that I do not! So I understand your frustration and yes, I think your headache is related to TMJ - talk to the orthodontist and oral surgeon when you see them just to see what they say.