Thank you mobiusmoon for your informed reply.

My head pain was originally your standard head heaviness, which many people with depression complain about. However, just over 3 years ago I experienced a major life stressor and that's when the heaviness intensified to the point of becoming pain. It has only progressed since then.

I've had two MRIs, nothing found. And it's not ptsd, I've seen a specialist who confirmed that for me. I don't think about the stressor anymore. The head pain has nothing to do with migraines either. Most doctors I have seen think it's related to the depression, though naturally I can't know for certain.
The pain fluctuates throughout the day in intensity but is always there.

Anyway, I appreciate your insight. I actually just had the chance to try cbd oil yesterday with a vaporizer and let me tell you, the pain has already loosened a bit. Unbelievable, it did more in a few hours than three years of painkillers have. I can't wait to see what medical weed might do. Although I've been disappointed so often before that I should reserve judgment.