If, how should I sleep with shoulder pain​ is what you are concerned about, shoulder pain diagnosis is a must. You need to see a qualified medical professional for this.

A doctor will ask for your medical history and perform a physical examination to find out whether or not there is swelling or tenderness of bones.

They might ask you questions like:

• Do you feel pain in one shoulder or both?
  
• Is it sudden, or comes on gradually?
  
• Is the pain faint or sharp, etc.  

Asking these questions will help them treat you properly.

They will also examine joint stability and extent of motion. Apart from physical examination, they are likely to perform imaging tests like MRI or X-Ray, as and when needed, to get a better insight into your pain and diagnose your condition in a better way.