What causes leg and arm pain that radiates to the fingers and toes?

Neuropathy: A nerve impingement in the back is the likely cause.

Radiculopathy: A pinched nerve in your neck may cause radiating pain down your arm to your hand and fingers. A pinched nerve in you lower back may cause pain that radiates down your leg to your foot and toes. Common causes of the "pinch" include disc herniations/bulges, or bone spurs/stenosis/narrowing of the spinal canal/foramen.