What Are The Shooting Pains In Head Of A Crystal Meth Addict?

I have a friend who does Crystal Meth daily. He sometimes gets painful shooting pains in his head which when happening are worse if he moves his eyes. It seems to me to happen mostly when he doesn t do meth but also sometimes when he does. He went to ER once and was told they r Spider Headaches but I can t find anything about that. He describes them as shooting, like a shock to his brain.