peripheral nerve distribution vs radicular pain

Can anyone help me out with the pathophysiological differences between pain felt in a dermatome and pain felt along a peripheral nerve distribution if the nerve injured is in the neck region. Since no nociceptors are involved if pain is caused by nerve compression...what starts off the firing of impulses to the CNS. What is the role of the nervi nervorum? Does ectopic firing take place without the need for nociceptor input? Any help will be much appreciated.