Got a sharp pain during sleep. around waist line, just above buttock. not in thigh or lower. relieved when laying on side. sciatic nerve likely?

Local pain condition: Both the nature of pain, as well as its localization help to determine cause. Anterior waist pain is different from posterior pain. Nerve pain tends to radiate more. Sciatic pain typically tends to be more lower back, buttock and into the posterior thigh regions and to the sole of the foot. Sharp pain in the "waist" could be non-neurological as well like from a kidney stone or muscle spasm.