This is what I was thinking. Blood flow. It feels like a cramp on my head. So strange.
I went to my myo therapist yesterday - I go for a monthly massage on my neck. I mentioned it and he said that he hasn’t heard of that. He massaged the muscles there … and now it is so tender.
I really wonder about how this contributes to migraines. Or a symptom. Thanks for the replies. Glad I’m not the only one.