To recap your history, you developed severe left posterior shoulder pain with paresthesias that radiated into the outside of your left hand about 5 months ago. You sat at a 45 degree angle to get some relief. I imagine that this included some neck flexion (forward head tilt). 3 Months later with PT, your pain was improved. One week later, severe pain developed in your neck with radiation into the left shoulder. I assume the radiation of pain and numbness did not go into the arm.
These symptoms are classic for a radiculopathy, probably of the C6 or C7 nerve. The reason lying down at 45 degrees relieved pain is to flex the neck which opens the foramen (see website under cervical radiculopathy) to relieve pressure on the nerve. I hope you had a thorough examination of your upper extremities to look for deficits in strength, sensation and reflex. This testing is the most sensitive for identifying the nerve root involved and if there is any motor deficit.
Your MRI I assume was performed prior to the new onset of severe neck pain. In my practice, after a new physical examination, a new MRI might be warranted for significant change in symptoms- especially if the physical examination has changed.
The radiologist who read the MRI notes “prominent” left disc herniation at C5-6 but did not comment on whether this caused foraminal compression. He does note a C6-7 HNP, which causes root compression. Either one of these or both could have caused your initial symptoms.
The increased pain four months later could be a recurrent herniation at either of the two levels that now caused some cord deformation. Recurrent herniations occur at the same level as the previous herniations and are due to the same process that caused the initial herniation.
Treatment depends upon the symptoms, the results of the physical examination (motor and cord deficits especially) and MRI/X-ray findings. Without significant motor or spinal cord findings, I would recommend an epidural steroid injection along with physical therapy to a patient with significant neck and shoulder pain who has already undergone previous therapy. Again, a new MRI might be warranted.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.