I suffered with this after taking a separate B vitamin.
I remembered reading that you should never take a B vitamin by itself, as it causes you to be short on all the other B vitamins.
After throwing that in the trash, and trying a B complex which has ALL the B vitamins, the symptoms left.
Interesting. I used to take a B complex that seemed to make my symptoms worse for RLS. Salt seems to lessen the RLS for me, and potassium.