I have been suffering leg and back pain since last 6 days.even i cannot walk.is it kidney infection or back bone problem? no swelling on any part .

Radiculopathy?: Sounds like lumbar radiculopathy, possibly due to a disc disease / herniation. Ct or MRI study may answer the question.

Likely back problem: Symptoms that suggest a back problem would be the back pain shooting into the leg, or weakness or numbness in the leg or foot. Any heavy lifting or trauma that triggered symptoms. Symptoms that suggest a kidney infection would be pain or burning with urination. Bladder or kidney infections aren't common in men.