Shady,
Adhesive capsulitis or a frozen shoulder can occur do to many different reasons. Sometimes, people who are multi-medicated can have drug interactions that can be the cause, sometimes it is secondary to an injury or tendinitis or in the case of the shoulder an impigement of the rotator cuff, or sometimes they are insidious in nature with no known cause. Firstly, it would be important to know if you know why you developed it. Did you have shoulder pain/tendinitis/inflammation prior to developing your frozen shoulder? It is not uncommon for persons over the age of 40, especially who are involved in overhead activities/sports or lift to have a subacromial spur that can cause rotator cuff impingement syndrome and cause the person to develop tendinitis and eventually adhesive capsulitis or a RTC tear. Literature suggests that you have 3 options with a frozen shoulder…some get better on their own with no treatment, PT treatment with joint mobilization and ROM, or manipulation under anesthesia. Remember that any thing medical with an -itis on the end refers to an inflammatory condition. If you aggravate your shoulder through weight training then you could impede recovery or even make the problem worse. My best advice without being able to see you myself would be similar to what your PT told you and that is to listen to your body. If it hurts while you do it or you have a persistent low-grade pain, not soreness, that last for over an hour after you lift then you are increasing the inflammatory process which is ill advised.