There are possibilities of Frozen shoulder
or Cervical Spondylosis
that is causing your problem. A simple X-ray of Shoulder and cervical spine
can rule out the problem. Accordingly treatment can be planned.
Regular exercise and physiotherapy
of the part along with analgesic and anti-inflammatory drugs will help you. Do alternate hot and cold fermentation of the part and try to mobile the shoulder after that.
Use hard bed to sleep and avoid pillow.
Hope this will help you