Headaches always in left temple relieved almost instantly by pressing right jugular...anyone know why?

Over the counter meds were no longer working for my menstrual headaches and I was absent-mindedly pressing my pulsing right jugular point midway up on my neck, et voila, almost instant relief. I tried this next time I had a headache (again left temple), not taking any meds at all and again, went away. I have been doing this successfully for a couple of months now, but I'm thinking what on earth do I have? This doesn't seem like a normal headache!! I am curious if anyone has ever heard of this...hours of googling have revealed nothing really matching this description.