Hi Raynebow! When I first started reading your post, I immediately thought that you must be sleeping on your arm...but then I saw what you had written about not sleeping in that position. Before you dismiss it though, consider that you spend 6-9 hrs (appox) sleeping. You don't really know how you are positioned that whole time. It's possible that you could be lying on that side, compressing the brachial (sp?) nerves of that shoulder/arm.
I have had that heavy/achy feeling in my arm as well, and I'm pretty sure it's from that same thing. A couple of things to try: A good (expensive!) memory foam pillow. This will put everything in good allignment, taking the pressure off the nerves. Stretching: Standing straight, brace your hand on the wall. Keeping your hand in place, rotate your body in the opposite direction as far as you can go. Hold for a few seconds, and repeat.
Try these and see if you get some relief. Please try not to worry about the thoughts of this possibly being a blood clot. I am not a dr., but I am very sure that it is not. The chances of a young, healthy person such as yourself having one, is not statistically worth even spending another second of concern on;)
How are you feeling othewise? I hope you are doing well:) Glad that you posted, hadn't heard from you in a while. I included you in our 'Shout Out to Missed Members' post:)
Let us know how you are doing soon,
"Courage is not the abscence of fear, it is feeling afraid and doing it anyway!"
"It is when we are most lost that we sometimes find our truest friends"
Panic Syndrome recovery due to CBT