Mine is in my upper arm also and i know the feeling, i am sure it was a nerve they hit, at least that is what they told me when they did it, it also felt like an electric shock through all that pain. I do hope those tests come back quick so you can get your transplant and get the hell out of dodge (well, out of the center that is)
Take care for now and just look forward to that gorgeous weekend you have planned for your birthday