Aerna has denied my claim 4 times

On September 29, 2014, I went to my doctor because I had back, neck, and arm pain. My doctor prescribed me medication, and gave me a letter to stay out of work until October 7, 2014. Aetna approved my STD for that time period, but when I went back to work part time, instead of working my normally 40 hours, Aetna would not approve my claim from October 8th, through December 2nd or for being out for the entire month of December. My doctor filled out all the Attending Physician Statements, listed my condition that was in his doctors notes, included the cortisone injections I had in my neck on 11/10/14, and 12/15/14. I faxed Aetna a copy of my MRI, and X-ray results, plus sent them a copy of a document listing the treatments I received at physical therapy that was written by the physical therapist, but Aetna still denied my claim. I filed an appeal, and explain in details why I believe my claim should be approved. Over, and over again, I did ask my doctor why it was not mentioned to Aetna on the physician statement that my Cervical Spinal Stenosis prevented me from working full because a major part of my job is data entry. I do suffer from back pain occasionally, but, my nerve pain comes from my neck, shoulder, and hand. My doctor, for some reason would not state what prevented me from performing my duties at work. I told them light lifting, and taking breaks from sitting relieves my back pain, but the data entry is the reason I had to be have my hours reduced at work. Aetna has denied my claim four times, which is really stressful, but the worse part is, since they did not approve my claim, and my employer was paying me my full time pay, I lost all my vacation time away, and is working without any paycheck until I all the money is paid back.