<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, Im experiencing a lot of shoulder stiffness and tightness. Its been going on for a while now. What could be the reason for this?  <response>: It sounds like you may be experiencing adhesive capsulitis of the shoulder, also known as frozen shoulder. A thickening and tightening of the shoulder capsule can cause stiffness, pain, and limited range of motion. 