My daughter, 15, has a lot of headaches but a bit different than you described. Unilateral, sharp, frequent, lasting 15 secs to 3 mins, then constant head pressure for hours. We can't identify the triggers. She is starting to try the med lamotrigine. I think her headaches are SUNCT or something like that. Was told by the neurologist that they are a "separate issue" than her POTS but she is susceptible to this because of her POTS. I tell you this because I understand that so much of this feels like trying to find a needle in a haystack. Best of luck to you.