When there is pain in the deltoid area, around the upper area of the arm at the shoulder, or at the insertion point of the deltoid muscle on the outer upper arm, it often is not due to a problem in the shoulder itself.
Rather, the origin of the pain is in the neck.
Misalignments or degenerative changes in the spine in the lower cervical region, at C6 - C7, can cause this pain that presents this way in the upper shoulder.
