I m still waiting for ansr.

 what could be best treatment to get rid of back pain. My 19 yr brother had back pain since march now that radiate to one leg some time both some time both hips.No history of trauma or anything it appears own its own and get worse day by day we consult with dr they proscribed  medicine & physiotherapy and said due to nerve compression pain is there.But whenever medicine stopped  pain appears again and again.since 20 days back we consult again to a different dr he ordered X-ray and told space reduced between L1-L2 and gave medicine but problem is same whenever medicine stop result is same. So plzz tell what could be exact cause or what would be treatment so he can get rid of pain.