I think this sounds more like persistent trapped nerve..
If i were you i would go out for a really long walk and swing your arms really hard as you stride for as long as you can... if its a nerve thats the kind of thing you need to do to pop it out of the shoulder blade
It sounds like you aren't exercising at all. If this is so, you are going to have pain. You must support your skeleton with exercise.
Do not go to that horrible doctor anymore.
I suggest you take up yoga or pilates or work with a personal trainer to tone up your muscles and improve your posture. Work out three times a week and try to walk briskly outside using good posture a couple of days a week, weather permitting. After three months, are the symptoms gone?
also to add to that... the pain when you breath in... it is in the shoulder right?... you dont mean pain in your lung?
ok.. where exactly on the shoulder blade is it... under it? on it? behind it?
are there any lumps that you can feel on or around it or under your armpit..
you should think about getting a new doctor.. thats a terrible attitude