Problem xitng spine. Nerves branch off in bundles from the spinal cord & exit thru an opening between the vertebrae. This is the nerve root. The opening itself is subject to narrowing or irritation from arthritis or various illnesses as are the tissues nearby. Nerve bundles are surrounded bu flexable tissue that can be compressed by the swelling nearby and end up choking off some of the nerve activity.
Called Radiculitis. Irritation of the origin of the nerve off the spinal cord (termed a root) that creates an inflammatory reaction leading to pain over that nerve distribution. That is called a radiculitis v a radiculopathy which is caused by nerve root compression.