I, too, have been through this process and I truly believe that they overwhelm you and your doctor with so much paperwork, hoping that you will give up. If it's Social Security Disability you are trying to get, they do hold you responsible if the doctor does not do the paperwork on time. You do have to keep on top of the doctors office, but if it looks like they are not going to get it done on time, I would suggest calling Social Security and tell them and they will note it in your file.
They recently asked me for a list of dates for every doctor's visit, test, scan, procedure, surgery, hospitalization, and prescription I have had filled for the last 2+ years. It was a massive undertaking! They never informed me to keep a record of any of this stuff, so initially I tried getting this information from each doctor, hospital, and pharmacy individually, until someone suggested that I call my insurance company which is split into two parts, one that covers doctor's visits, out-patient testing, and prescriptions, & the other covers surgeries and hospitalizations. Because I needed more than 18 months worth of information, I had to make a request in writing which they "did not get or lost" twice, until I sent it registered mail, return receipt requested & it still took them about 3 months to get the information to me - Social Security had given me 30 days to get it all and get it sent to them.
I called the insurance company once a week until I got what I needed (make sure you get the name & extention of the person you talk to), and every other week or so I would call Social Security and let them know what was going on.
I would also suggest being very detailed when answering questions on any paperwork they send you, and definitely keep copies of everything because if you are approved, approximately every two years they will "re-evaluate" your condition, and they will ask you the same questions again and it helps to know what you wrote before so you can be specific about what has remained the same and what may have gotten worse, etc.
They will ask you what you do every hour of the day, every medication you have ever been on and if you stopped taking it they want to know why. The last "re-evaluation" they did on me they sent me 25 pages worth of questions, and sent each doctor 18 pages worth.
It is overwhelming, but not impossible. I was approved on my first attempt at getting Soc. Sec. Disability, which they say is almost impossible. I hope these tips will be helpful.