This has bothered me for five years..and happens when I'm sitting, standing and lying down. It has happened when I least expect it...never at night however when I'm asleep or just wake up. It comes on within about one minute with no other warning than a weird feeling that I need to stop and give this my full attention because it is going to hurt like hell....it is going to make me feel like I need to stop talking, lie down and pray I don't die. What is it? I finally came to the conclusion it might be related to fibromyalgia. I do have TMJ...but this is different. It scared my oldest daughter so much she wanted to immediately take me to the hospital when she was with me and I just froze in pain. In 5 to 10 minutes its all gone but those minutes leave me terror stricken that something is very wrong. My right lower jaw feels like it is being crushed and it is totally immobilizing. I really would like some feed back on this and am curious to know if anyone else has had anything similar anywhere in their body that only happens 3 or 4 times a year..but happens year afer year. Thanks..you are all such a big help on this board.