Commonly found with the upper trapezius
Chronic neck and shoulder pain is almost always associated with the trapezius muscle. This is a complex muscle often called “The Coat Hanger” which can also refer pain into the side of the head and at the base of the skull.
This pattern is commonly caused by chronic elevation of the shoulders when carrying a heavy purse, bag or briefcase, sitting in a chair without proper armrests, side impact injury to the shoulder and long term compression of the muscle as with tight bra straps or a heavy coat that does not fit correctly.
Treatment of the muscle itself should be directed at the “x” and often responds well to heat and massage. This is a particularly difficult muscle to reach so I recommend using a body back buddy or a TP Therapy massage baller. There may be other areas of compensatory muscle strain associated with this neck and shoulder pattern, which is often relieved with the self-massage but if symptoms do not improve or worsen consult your health care provider.
The areas marked by an “X” are the main points of strain and the red areas show pain referral patterns that result.
Illustrations from Myofascial pain and dysfunction: the trigger point manual by Travell & Simons