Sir,
Firstly you need to rule out if the pain is coming from the shoulder or the neck.A thorough evaluation will help in planning out the treatment for the same.
Next Steps
you could meet with a physiotherapist close by your residence and get yourself assessed.
Health Tips
-avoid things that give pain around the area.
-do not lifts heavy weights.
-can apply hot water fermentation around the area might help to reduce the stiffness around the shoulder and neck region