I think i have sporadic fatal insomnia i can't sleep because my brain don't feel sleepy i can't produce tears, i have muscle spams, pain in the neck ?

Very unlikely: Primary fatal insomnia is extremely rare. I would check a metabolic panel with thyroid, liver, and vitamins. There is good treatment for insomnia including cognitive behavior therapy. A sleep specialist can evaluate you.

Evaluate: Have your primary care doc evaluate and refer you to a specialist if needed. There are many treatments that can reduce some of your problems while the diagnosis is being determined.