Pain in the back radiating to legs usually caused by lumbar spine problems like disc prolapse etc..it needs neurological examination and imaging..consult a neurosurgeon and follow his advice..

Pain in the buttock radiating down the back of thigh is suggestive of a clinical condition called Piriformis Syndrome..wherein the sciatic nerve gets entrapped under the Piriformis muscle resulting in pain distal to the area. People with prolonged sitting or standing occupations are more prone to develop this condition. It is advisable to get in touch with an experienced physio for effective management of the same.

It needs proper evaluation. Seems to be due to some nerve compression. Kindly revisit the doctor Few investigations for proper diagnosis and change of medication may be required