HI

taking into consideration is no cervical/neck problem, i can agree with physiobob.
But i have seen very similar problems caused by disfunctions of scapula/shoulder girdle, especially trigger points in muscles inc infraspinatus, supraspinatus, middle and lower trapesius, rhomboideus, subscapularis muscles.

please, learn about trigger point next about muscles, then ask someone to assess it.

Obviously their existance are part of a complex - neck, scapula, back, posture, reaction on a mental/social stress.Very often locomotor malfunctions are visible in scans

all the best