hi megan.

have you ever been to see a physiotherapist regarding your pain?

you obviously have a definitive reason for being in pain, degenerative sc joints but i imagine there are probably a fair few associated issues that may be adding to your pain.

the whole shoulder girdle system (clavicle, sc joint, ac joint, scapula, scapulothoracic joint, shoulder joint) is quite complex and in order for it to function correctly requires that the particular joints have a certain amount of range of movement and that local stabilising muscles and larger moving muscles work in a particular pattern to allow us to move our arms while maintaining functional stability at each of the segments.

the sc joint really doesnt have any particular stabilising muscles of its own but it is certainly a possibility that if you were to focus on retraining altered muscle recruitment patterns around your shoulder while also re-educating your posture and treating areas of stiffness you may experience an improvement in your symptoms. in theory you would be trying to "offload" the sterno clavicular joint, to what extent this could be achieved i am not sure but it would make sense. the stronger you are along the kinetic chain that is the arm/shoulder/upper trunk the less force that the sc joint may be under.

things that i would look out for are poor posture (neck, scapulae, shoulder, thoracic spine etc), poor scapular control statically and dynamically through range, stiff thoracic spine, stiff first rib, weak deep neck flexors, weak serratus anterior, weak lower traps, tight anterior shoulder structures and on and on and on......

so basically i would be looking out for a lot of things!

i'd recommend that you do a bit of research and try and find a physiotherapist close to you who has experience and an interest in treating problems around the shoulder and neck. go for an assessment and see what they thnk. you really dont have anything to lose.