Common treatments for fibromyalgia are anti-inflammatory medications, opioid pain medications, and corticosteroids. A 2011 study that focused on CBD treatment for fibromyalgia produced very promising results for future uses in treatment. Half of the 56 participants used Cannabidiol, while the other half used traditional methods to treat their condition. Those that used cannabis saw a great reduction in their symptoms and pain, while those using traditional methods didn’t see much of an improvement.
Pharmacology published a study in 2016 looking at medical marijuana for migraines, specifically in relation to its effects on serotonin, with very positive results. You’ll notice that neither study looked at CBD in isolation from other cannabinoids (which is an issue with a lot of research on CBD and pain). Truthfully, the research on CBD alone just isn’t sufficient to make any pronouncements about its effects on headache pain.