Our Peoria Chiropractic gets many questions on the cause and the treatment of Frozen shoulder.  Frozen shoulder (more formally known as adhesive capsulitis) occurs when the tissue of the joint capsule in your shoulder swells and thickens, causing pain and a reduction in range of movement. It can occur in one or both shoulders, or sometimes even move between one and the other. The cause of frozen shoulder is not exactly known, but there are a number of risk factors that can lead to this problem and a wide range of treatment options, depending upon the severity of the disorder.