Had the same thing three years ago, calcific tendonitis. Had cortizone injections, which wore off after less than an hour, then hospital for x-rays etc, and a course of physio of about a dozen different exercises/stretches, to be performed three times a day. That started working after a few days, could feel it freeing up a bit, and pain easing. Kept the stretches etc going for a couple of months, til my shoulder was practically back to normal. Still do a few of the streches etc a couple of times a week, to keep it mobile.