have you been checked out for Dystonia? I have in my case cervical Dystonia (funnily enough cervical Dystonia is in the neck) I also have no Dopamine receptors.
The only other time I have met another person with Dystonia was in her leg, both of us have had blackouts followed by convulsions, caused by intense pain from the Dystonic reaction. Hope you find out for certain what the diagnosis is.
Good luck and God bless