help with shoulder problems?

I have been going to the doctor about my shoulder because of lots of pain I'm expirencing. I really can't move it it comes and goes from one day to another. she says its just because of me not having equal amounts of muscle she says my left shoulder has more muscle then my right and that's what's causing the pain and says I have inflation. I'm not really sure what it trully is but hopefully someone can help me. and the pain is around the shoulder cuff and the muscle on top of my should but feels like it's interior pain