I read your post and it very well could have been written by me. I am in diagnosis limboland once again myself.
I don't have CFS to my knowledge, but also have fatigue and pain, as well as other symptoms. At this point I am at the mercy of my oncologist and neurologist and whatever appointments and tests they set up. It really makes one feel they have no control over their own life.
Something I learned when I was undergoing cancer treatments, was to stop comparing myself and my life to anyone else. I learned to do what I could, when I could, and not worry about the rest. I miss the old me - the one who had endless energy, the spotless home.....but she is gone and not likely to come back. Acceptance is a very hard pill to swallow, but once swallowed, it frees you to make the best of who and what you are now.
Keep pushing your doctors to figure out what is happening with you. They may have all the letters after their names and the fancy papers on the wall, but YOU know your body and when something is not right with it. Even though my cancer is more than likely in remission right now, I know something isn't right with me either. When my original oncologist told me to come back when "I had symptoms", I fired him. I now see an oncologist who reminds me of a Tasmanian devil.......never stops...lol. He has tested my blood for everything except PSA (I'm female, no prostate....that I know of...lol) and I am having PET, CT, and MRI scanning from head to toe to be sure the cancer hasn't snuck back, and to find out what is causing my symptoms.
Your doctors work for you. You can fire them. Sometimes it takes a long time to find out what is wrong. It took me three years to be diagnosed with sarcoidosis, after being called a hypochondriac and Munchausen case. When it finally manifested itself in my lungs, I had a thoracotomy and was finally correctly diagnosed.
In the meantime, be good to you. Find things to do that you enjoy and don't take all of your energy. I crochet hats for chemotherapy patients. Knowing that I can touch someone's life without even meeting them goes a long way to helping me feel good about myself. Sometimes we just have to find new ways to do the old things :)
I wish you the best of luck in your tests.....and will watch for your posts :)