Had brain spine MRI blood test emg all clear except slight fasciculations neuro sais bfs but I have pain constant inner tights can it cause this?

Sounds like. A normal complete work up that leaves a diagnostic mystery only thing i didnt see on list was a bone scan fasiculation are imperceptiable muscle twitching sign of electrical activity in the setting of a pain workup should rule out important nerve dysfunction if you can't find a diagnosis or have a untreatable diagnosis consider pain consultaition for paliative care plan.