I was diagnosed with brachial neuritis in 1991. I had a month of excruciating pain in my right shoulder which was treated with Percodan. My diagnosis at the time was tendinitis and I was given a sling. As the pain subsided, so did sensation at the surface of my skin along my deltoids, scapula, and down to the extenders for my fingers. This was first noticed by my physical therapist with a pin ****k test. She immediately had me referred to a neurologist who had never seen a case like mine in his career. He recommended a TENS (trans-dermal neural stimulator) to stimulate the muscle groups and advised that neural tissue doesn't regenerate well. If I was lucky, I might see improvement of 1 cm per month. The numbness and paralysis was already extensive and it was too late to save the deltoids. To this day, it's still atrophied, however other compensatory muscles in my neck allow most normal activity. The extenders to my fingers remain at about 80-85%.
In 2010, I developed the same pain in my left shoulder and knew immediately what I was dealing with. If you've experienced this pain, it's unmistakable and allows virtually no relief for sleep or work without treatment. I researched online, discovering that the medical profession has not advanced in this field. In my profession I could not afford to be drugged, so I ordered an $80.00 TENS unit online and used it effectively as a pain blocker (creates "white noise" in local area when the electrode pads are placed on either side of the pain center with continuous pulses at a medium intensity...you have to experiment as units differ) to sleep and work, as well as for muscle stimulation to prevent wasting. Determined to have a better outcome this time, I used range-of-motion and light strength exercises (this will test your thresh-hold for pain) until the pain subsided (about 4-5 weeks) and then began swimming and using heavier weights (don't over do it as the soft muscle is sensitive will be very sore for a few days following weight training). 3 months later, I have regained complete control of the muscle groups.
In my online research, the problems with this condition appear to be that it never seems to be diagnosed quickly enough, and the advise given by "professionals" is frequently misguided. I have seen articles recommending resting the arm in a sling and simply treating the pain with narcotics. This, I can tell you, is a guaranteed recipe for failure. The muscles MUST be stimulated early and often. I now know it can be treated effectively with exercise and stimulation if diagnosed early enough (within about 10 days of onset of pain).
I hope my experience is helpful to others with this rare condition.
Brian in Colorado.