If you do have RSD/CRPS, immobilization is one of the worst things for you. The brace should probably be taken off until you receive a diagnosis one way or the other.

The key is to find a doctor who has actual EXPERIENCE treating CRPS. Hopefully the Rheumatologist you are going to be seeing will be helpful. This condition is widely misunderstood, even among professionals.

Aquatherapy, if it can be tolerated, is a very good idea. It gets the body moving in a gentle manner without impact. I'd certainly recommend it. My mantra is "use, but don't over-use".

You mentioned that it has been 10 years since the knee pain started. Did you injure it or have surgery on it just before the pain started? Or did the pain just start mysteriously? The answer to that question is pretty important. Exactly what type of knee surgeries did you have?? What is your diagnosis from the orthopedic surgeon? There are a lot of variables in play when trying to make a CRPS diagnosis.