tchair

No it's not in your head, but dealing with it in your head (the frustration and resulting depression) can be as difficult as the pain itself. After some years of dealing with pain, I now refer to it as the 'Alice in Wonderland' situation. You might get an adversarial response rather than co-operation, and hear them say 'She's off of her head!'.
Part of the problem is that doctors are analytical. They cannot (and you wouldn't want them to) prescribe or operate without proof of necessity. Since their patients and peers are not amenable to an answer of 'I don't know' they must produce a diagnosis. But too often it seems that a psychological determination is made not because it is appropriate, but due to the lack of physical evidence to display.
I've seen this with a neighbor who had reported feeling very sick, so much so that he had made mistakes on the job. This was turned around to - you must be feeling sick because of the mistakes. In other words the doc revised the actual events and branded him a liar. He as sent home with a roll of Tumms and told to 'calm down', only to require an appendectomy just hours later.
I experienced this with two physicians (I will not call them doctors). One was quick to diagnose depression, not because of clinical signs, but because he had not reviewed my records and was not aware that I was recovering from a severe fracture which would account for my pain. Another ignored my complaints of medication side effects, pointing to my symptoms as classic signs of depression. That was until his nurse found that I was suffering the exact adverse reactions attributable to the level of a medication in my system. I believe my 'diagnosis' was due simply to his refusal to appear less than infallible by refering to his resources or asking a subordinate. The appology which followed also had nothing but protecting his ego in it's intent.
Like everyone else with chronic pain, I have been down when pain resulted in sleep deprivation, difficulty performing at work, and home life getting askew. Countless numbers of us laymen have a response for that - Treat the real problem - pain, and that will take care of this symptom - depression. Too often they resort to anti-depressants, adding physical and psycological side effects on top of the untreated pain.
I'm going on some, but this is a whole world that you will be entering. My first advice, yes you can trust yourself, if it hurts it hurts. Avoid using 'emotional' terms. Pain is not 'gnawing at you' it is a gnawing sensation'. Pain is not awfull, you don't hate it, and you don't want to scream. It is sharp or dull, constant or intermittent, always described in objective medical terms. It may sound stupid but how you say it can be taken as more important than what you say. "Withering away" is correctly phrased as - experiencing a decline in normal activities and general quality of life. I am serious about this. Report accurately to doctors in the terms that they are restricted to.
I don't know RSD specifically, but strongly advise you to check on these forums, basically for mentors to facilitate your progress. There is no way to ensure what you read is accurate, from a good source, or is not simply unique to only one individual. Much is biased, some is promoting products, and although I've 'bashed' a few doctors here, I would never follow any advice without consulting them first. Your job will be to get them on your team as they will be the ones you will be depending apon for relief.