Upper neck pain and pain that radiates into the lower skull (although not typically to the jaw) can originate from upper cervical facet disorders. These disorders are not related to lymph node enlargement. An MRI of your head to include your jaw might be helpful. There are disorders of the jaw that can cause pain and enlarged lymph nodes.
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.