Here is a partner stretch for the pectoral muscles that I often implement with patients who have shoulder, neck, or mid-back pain issues. This can also be a good technique if you work at a desk or on a computer and find yourself in a rounded shoulder posture often throughout the day.
A similar doorway pectoral stretch can be found in several of the rehab programs in my book. In my book, each body region has its own chapter. The shoulder chapter includes programs for rotator cuff injuries, frozen shoulder, shoulder dislocations and labral tears and biceps tendinopathy. Click the link below to learn more about my book.
https://amzn.to/3UqyKOf