X-rays will help your doctor
diagnose broken bones, a dislocated shoulder, and possibly osteoarthritis in the shoulder, but will not be able to tell you anything about the muscles that make up the rotator cuff. For looking at the soft tissues within the shoulder, MRI is the best imaging modality. IV contrast can be used to help increase the sensitivity of the test, but the radiologist
may have either decided that this was not the case or that you were not the best candidate for receiving the contrast.
In any case, if conservative management of your shoulder pain, including physical therapy, is not making any difference, then it would seem reasonable to ask for a referral to an orthopedic surgeon
. He/she can perform a more detailed physical exam looking for weakness related to any of the 4 rotator cuff muscles. With that information, the MRI scans you have already undergone can be reviewed or repeated looking for a correlation to the exam findings.