Both me and my twin sister have had this issue since we were kids. It only happens a couple times a year since we try our best to avoid the triggers. Our trigger is typically yawning and moving our neck or yawning with our neck in any bent or turned position. I am assuming this isnt a disease or anything that a doctor will be able to diagnose. I am convinced it is just cartilage/ligaments in the neck moving and popping out of place. Maybe its because we all have slightly different anatomy in the ligaments that allow this movement. Both me and my sister have a different technique to fix it so i think you just have to see what works for you. I used to be able to chug water and push a little lower than where you take ur pulse. That stopped working for me and now I have to open my mouth wide and bend my neck to the side and push it back in place. My twin sister basically does a low moan noise and it pops back into place for her. I also notice that once it happens to me, I am more prone to getting it in the near future. Like i went 2 years without getting it and then had it happen twice in a week. Maybe it causes some inflammation and then its more likely to pop out of its positon