Carpal tunnel syndrome can cause pain that extends up the arm towards the shoulder as it gets worse
I suspect that you use your hands a lot at work? the swelling may be some associated bursitis(swelling of the fluid around the muscle-bone attachments) for the same reason
I cannot tell you for sure as I have not examined you or seen your EMG results
MRI and EMG should be able to exclude a problem in the nerve rots at the neck or in the spinal cord
If the last EMG was last June, it would be worth repeating to see if it is worse, or is serious enough to consider surgery
Good luck!
PW
Have you tried UPPER CERVICAL SPECEFIC CHIROPRACTIC? Chiropractors who specialise in that area tend to take a different approach and use unique tools. Your atlas (top bone on the spinal column) is higher up than you'd think. When mine was put back into place it felt like something moved inside of my skull! Definetely a strange feeling but not really any more painful than what I already felt. Other chiropractors could not help me AT ALL and could not find anything wrong. I had an MRI done as well as numerous other x-rays of my neck. Did your chiropractor take any x-rays from the front with your mouth open? That is one of the ones where you can actually see the atlas. Mine was out by quite a bit (in the x-rays it looked like a half inch but I'm not sure how far in reality).
I too had symptoms that were varied and would occasionally come and go, and since you said resting helps a little, it sounds like your problem is more related to movement or that it is aggrivated by movement. I hurt all the time but was definetely worse with movement, standing, or even sitting in a chair (I also worked with a computer). Proper diet and excercise are also usually beneficial to overall health and wellness. Pilates workouts have helped immensely with training the muscles in my body to maintain correct posture which relieves quite a bit of pressure on my spine and will help to hold my atlas in place. Its sometimes hard to believe that such simple things can help such extreme conditions but barring actual injuries (ie. torn or broken parts of the body), diseases, or other noticeable and definite problems, these things can help. Check it and a UPPER CERVICAL SPECEFIC CHIROPRACTOR out. I know from experience that its hard to be patient but hang in there. I'll pray for you.