Neurofeedback won't be able to diagnose a headache or migraine because there really are not typical brainwave patterns for these. Your headache or migraine is most likely a manifestation of brainwave irregularities in your EEG. So, instead, the therapist will be able to discern those irregularities and attempt to normalize them. When this happens, often the migraines or headaches go away. However, as a side note, migraines can be a bit trickier to treat because sometimes they aren't related to EEG but to other factors such as lack of blood flow to that area. However, HEG is a good therapy for this condition.

No one really knows why neurofeedback isn't more mainstream. One theory is that before the discovery of neuroplasticity, mainstream medicine didn't believe the brain could change at all, so they dismissed the idea of being able to change your brain through conditioning. Another theory has to do with ADHD. Neurofeedback has been proven through scientific studies to be as effective at treating ADHD as any medication has. Because of this, the pharmaceutical companies have worked hard to keep neurofeedback out of mainstream medicine. A third theory is that it is difficult to perform double blind placebo studies with this therapy, so they have had a difficult time getting the FDA to clear it, and since it isn't FDA approved, a lot of doctors won't prescribe it. Finally, it isn't taught in medical school, so a lot of doctors simply don't know anything about it.