This happens to me too! It's very hard to find any info on it. It doesn't happen often and sometimes I feel it coming on and I'm able to stop it with slow movements in my neck. The worst one I have ever had was today and it lasted about 20 minutes. Normally I can massage the area and move my neck until it goes back into place, but that wasn't working. I had to video chat with my mom and type through a conversation with her trying to find something to help. She found something that said I should try to sit up straight and slowly look down until my chin touched my chest and then look up SLOWLY. It hurt to look down but after I did it once I finally had relief! Then I had a panic attack. But walking around, deep breaths, and continuing to slowly look down and up made me feel better. Thankfully she found that exercise and hopefully it will work in the future and possibly help someone else!