[header] How to diagnose a frozen shoulder [title] Check for stiffness and pain in the shoulder. [step] The first stage of frozen shoulder is the " freezing " phase. In this phase, you will experience stiffness and pain in your shoulder that builds up over time, usually 2-9 months. 
The onset of pain is slow and gradual and localizes near the deltoid insertion. Most people describe it as achy, but it can become sharp when the affected shoulder reaches its extreme range of motion.