Neck pain origin is more difficult to determine than shoulder/arm pain is. The pain can originate from many different levels and selective blocks are one way to determine origin of the pain. See:
https://neckandback.com/treatments/epidural-injections-and-selective-nerve-root-blocks-diagnostic-and-therapeutic-neck/ and
https://neckandback.com/treatments/diagnostic-therapeutic-neck/
Dr. Corenman