With "lot's of pain", and being an MT, you can imagine what my suggestion would be... find a therapist to work on you regularly.
If you have already tried some at-home options and they are not working, then you probably need more specific work.
I wouldn't use an occipivot until you determined the cause of the issue, in order to know if it is the right tool or not. It sounds like you are guessing at this point and guessing can cause you to create more injury to yourself, if you are not careful.
I hope you are able to find a path for healing in the near future.
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view. May your mountains rise into and above the clouds. May your rivers flow without end, meandering through pastoral valleys tinkling with bells ...