Radiating nerve pain is a burning or knifelike pain radiating down the leg, ribcage, or arm. This is usually accompanied by a duplication of the pain when coughing, sneezing, laughing, or bearing down (known as Valsalva's sign).  This is usually caused by a bulging disc between the vertebrae.  Radiating nerve pain can be more complex than simple back or neck pain, as it indicates a more severe injury.  Most of the time, though, it is quite treatable.