Find a VERY Good Ortho and get his advice. Some times bursitis is the problem and you tend to baby the shoulder and it becomes frozen. Sometimes shots and PT work. Sometimes it takes the Dr. giving you a knock out shot and breaking it free, then PT.
Don't go to a reg. GP as they don't have the knowledge to work on this type of injury.
Think about how if any that you favored it and after you get your diagnosis--work past it.
Remember the Cortisone shot are usually a short term fix. But if you get them before PT it may help you get better.
Let us know when you go!!!