I have had pain in the back of my head for a year or so. Have been for physio and acupuncture but nothing helps. A few days ago I woke up with a severe pain in the back of my head, and went to emerg for relief. They gave me an injection to relax muscles and a pain med. it zonked me out for the rest of the day. Also gave me a neck support. Now I can feel the pain coming back but putting on the neck support keeps it from becoming fulblown. What is going on with me. Emerg people told me I was having a muscle spasm. How do I stop it.?