Hi, I Am In The Medical Profession, My Husband Complained

Hi, I am in the medical profession, my husband complained of pain down his left shoulder and back. His Internest, felt the area,and told him that it wasn't arthritis. He had a MRI, the same day. His Dr. Called and told him that he woul schedule an appt. with a Neurologist. What are your differentials? There are other health issues involved. I need to check these before I continue.