Usually a block is performed to determine if there is damage to the sympathetic nerve chain
and if
it is the source of pain. This
is a diagnostic test primarily, but
it may provide relief far in excess of the duration of the anesthetic. I had a very similar diagnostic test for my SIJ. It diagnosed my severe SIJ Dysfunction beyond doubt.
Nick is correct that this site does not tell you how to obtain narcotics but certainly for pain sufferers we make suggestions on who to consult.