I'm 16 and my shoulder, and under my trapezes muscle has been hurting for a while now( 1-2 years) , it cracks a lot when i rotate it .

TRAPEZIUS: It must not be bad, otherwise why have not you seen a doctor !trapezius muscle originates at the occipital bone ( back of head), and neck vertebrae and upper back bone ( thoracic vertebrae). It ends at collar bone and shoulder blades ( scapula). Causes of shoulder pain are numerous ! it depends upon what type of activities you are engaged in ! tendinitis, bursitis, impingement are common.