My orthodontist just told me I have the same kind of disc displacement. She told me to just move my lower jaw side to side and try to fix it that way.. Maybe that'll help you...
It can be caused by excessive gum chewing, grinding teeth, or problems in the way your teeth fit together/bite..
Haha.. ya I realize it's been a long time since your post was put up, but, I found it by googling TMJ to learn more about it.