Ali
Sorry I missed your post somehow, I want to reach through the computer and give you a hug.
I truly hope it is just a combination of stress that is causing what my physio calls an 'rsd reaction' rather than a straight out spread. All my fingers are crossed for you and I'm praying too.
Are you taking vitamin C by any chance? there have been studies that have shown it to have some benefit and its a natural supplement rather than meds and also salmon oil or some fish oil (salmon is the purest quality) its a natural anti inflammatory that my dr gets me to take also and I feel better for it and I dont think its placebo. Keep getting your Mum to very lightly massage your shoulder and arm if you can bear her to, also in the bath gently move your arm under the water if you can get it deep enough, hopefully that will ease the pain a bit. I know not to tell you to keep moving it as I know you tell everyone to do that
I might also suggest taking plain old paracetamol, or similar (not sure what you have in the UK)...just as if you would have before you got rsd and hurt yourself, it may still be an accute pain that is happening and trying this wont hurt you.

And above all, try and de-stress, forget about the mess that has been going on, focus on your studies and your bright future, your trip to Vegas and the coming spring...remember those all important happy hormones!

Dont forget I am here for you, just need to say if you need anything.

Take care sunshine