To differentiate pain generators from neck vs. shoulder, diagnostic injections should be used. If a shoulder injection relieves your pain, most likely the pain is shoulder in origin. If a selective nerve root block of the 1-2 roots yields relief, then most likely the neck is the source.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.