I would suggest that you see an Osteopath. They are doctors too but they have extra knowledge about Dislocated and / or Pinched Nerves. You could have some of those problems in your back.
Meanwhile and until you see an Osteopath, do this acupressure technique every time you have it that I am giving you now as follow: " use you thumb and index finger of your right hand and place your thumb between your index bone and thumb bone, on top of your hand, where they join in you hand and your index finger opposite your thumb inside your left hand. On the soft tissue between both thumb and index. Do not dig in with your thumb and index. Instead, use both pads and apply pressure with your thumb on top and equalize it with your index finger underneath. Keep this pressure on till your headache is gone. Once you have done this to your left hand, you could do it to your right hand too. Depending on how long you had your Headache / Migraine, it will take up to 15 minutes per hand. You could do 10 min. the left hand and 10 min. your right hand ".