This sometimes works for me:
I take a tennis ball, put it in a long sock. I lay flat on the floor. lift my head slightly and with the help of the sock position the ball so that when I rest my head back down, the tennis ball is hitting that space at the top of the neck/ bottom of the head . where you feel a space between bones... I think there are pressure points (not certain) but work it into that space... it may not feel very pleasant at first... and may need to only do it for a minute or two at a time. But it has helped me deal with a migraine.