Hi, many thanks for the query!
Well, this seems more like Sciatica
, pain due to compression/irritation of sciatic nerve
or of one of five spinal nerve
roots that give rise to sciatic nerve.
This needs confirmation with physical examination by your doctor.
Treatment is according to the cause of sciatica & severity of pain.
To know more about kidneys, you need to do- RFT, USG KUB, Urine (R/M).
Wish you a good health.