I am so sorry to hear you are in such pain. It does sound like Frozen Shouler though. The freezing stage is extremely painful. I have had frozen shoulder in both shoulders. I am in the unfreezing stage on the left after three years of frozen shoulder. be careful if they want to give you any cortison shots as this does not always help frozen shoulder. I am actually thinking that the cortisone shot that I had for my frozen shoulder might have caused some damage and possibly RSD based on how its acting.

If it is frozen shoulder look up the Neil Ascher technique and try to find a therapist that treats this way. I hear that they have pretty good success with it.