I've had a constant ha for the past 2 yrs and i started passing out a week ago. i went to the hospital, its not migrane and they don't know what it is?

Long list of possibl: Labs for thyroid, anemia, glucose, etc. Hormone evaluations. Low blood pressure? Look up "shy-drager syndrome ". Structural possibilities include arterial/venous outflow obstructions- suggest MRI of head, ct angiogram if detailed history includes blacking out, vision changes or memory loss. Brachial plexus study if above normal. Eval with neurology/neuromusculoskeletal specialist the best idea.