I have almost the exact same problem. My sister actually sent me your post. It's been going on for like 10+ years. It use to only happen every once in awhile, but the last couple years it's been happening almost daily. Mine happens when I move my head a certain way, sometimes when i yawn or lean back. It hurts so bad to swallow when it happens..or even moving my head. It's like I can't think of anything else. I panicked when it got stuck for a day and went to urgent care. I told them I can usually push it back on my own (i open my jaw and tilt my head back when pushing). They had no idea what was going on. They said they thought something was stuck, and that the longer its stuck the more irritated the muscle becomes. Then it swells making it harder to move back. They didn't have an ultrasound machine at the time so they just gave me some pain meds and a couple different muscle relaxers. I was able to push it back after an hour. My doctor ended up giving me muscle relaxers that dont always work. Might be because they're weak? I saw a nose ear and throat doctor as well. Showed them a video of me pushing it back and the popping noise it makes when it happens. Im glad I brought the video. He thought I was describing it wrong and it was something different. He brought in another doctor to look too. Neither knew what was going on. Sent me for a ct scan of my neck, but my neck was normal when I got it done. They said everything looked fine, but they want me to come in when it happens again. Hopefully get an ultrasound in the future when it happens. My doctor had me do multiple ultrasounds of my thyroid, but the ent dr said they really don't think the thyroid has anything to do with it. I really hope you get some answers. I understand how painful and frustrating it can be.