Dear Bikelet,
Because the serr ant is not easy for a self treatment, you may need a therapist to do this. The clavicle gets torsion from the subclavius. This is often overlooked in therapy. You might get checked for thoracic outlet syndrome or as some term it thoracic outlet compressio syndrome.
Since the pec minor attaches to the coracoid process, it would be sore or tender. You will have to find cause vs effect. This is often harder that what is hurting.
Best regards,
Neuromuscular.