If you have a rotator cuff injury then medical advice is exactly what you should be seeking. Plenty of us here have had rotator cuff and similar shoulder problems. Many of us have indeed self addressed the issue; (Some successful; some not) but that doesn't mean that you should. We are all different. My recommendation is to follow your doctors and physiotherapist's advice.
As one of the people here who have had rotator cuff problems, I'll share my experience, which is (hopefully obviously) not a substitute for medical advice, or advice itself.
I have had arthoscopic repairs for supraspinatus tears in both shoulders at different times. Both tears were due to acute injuries incurred while playing basketball.
The first injury also included an obvious tear of the biceps tendon (long head). The surgeon was optimistic about being able to repair both the biceps tendon and the rotator cuff, but said that if I waited to have the surgery the chances of being able to repair the biceps tendon would diminish over time. This caused me to opt for surgery immediately without trying nonsurgical rehab first.
The surgeon was not able to repair the biceps tendon after all, and although he deemed the rotator cuff repair "successful," it was actually ultimately a failure. I went through recovery and rehab, and met all the benchmarks for the the physical therapists to release me from therapy, but my shoulder was still painful, the range of motion was still limited, and it just didn't feel right. I actually felt worse after surgery than I had before.
I got a follow up MRI and sought additional opinions from two other doctors. Both told me that the MRI showed a supraspinatus tear, and that with that MRI and my current symptoms, a second surgery was recommended.
I actually had a second surgery sheduled with one of the new doctors, but cancelled it at the last minute and started a trial and error self-treatment program. Ultimately, I was able to rehab my bad shoulder to the point where I have minimal pain and relatively full function. My range of motion in external rotation is a little restricted, and I have occasional mild twinges, but I can basically do anything I want with it -- pressing overhead, snatching, heavy clubbell and mace work, basketball, throwing a ball or whatever.
The second tear was a lot more initially severe, and the doctors I consulted all recommended surgery. But based on my first experience I was very leery of another surgery and was determined to avoid it.
BTW, rotator cuff surgery really, really, really sucks. The recovery is very long and painful, I had to sleep sitting up in a chair for over six weeks, wearing a sling is extremely uncomfortable, and my normal activities were extremely hampered for a long time. So on top of the bad outcome the first time, I definitely did not want to go through that again.
Based on what I had learned rehabbing after the first surgery, and being able to avoid a second repair on that side, I was hopeful that I could rehab the new injury and I worked really hard and consistently at it for months. But it became apparent that it just wasn't going to work. There was actually a lot of training I was able to do with the bad shoulder, it improved a lot from the time of the injury, and the doctors I consulted were amazed at what I could do despite the injury. But I was still in a lot of pain, couldn't sleep on the injured side, and was substantially functionally limited. Progress then plateaued for a long time, and it seemed clear that it just wouldn't improve further.
So I had surgery on the second side with a new doctor who I felt very comfortable with. The recovery and rehab were still very long and unpleasant, but ultimately successful. In addition to the prescribed physical therapy, I also employed a lot of my own self-designed therapy (in consultation with my doctor and therapists), some of which is listed below. That shoulder is now completely pain-free and fully functional.
Here are some of my big bang for the buck shoulder tuneups that have gotten and keep my shoulders feeling great.
--Original Strength crawling and rocking variations.
--The David Allen band pull-apart super series:
--Mace and clubbell swinging.
--Dislocates using a PVC pipe (I didn't start noticing results from these until I did them very consistently and patiently over time, keeping my hands at a comfortable distance and not trying to force progress).
--KB snatches.
--The D I C K Hartzell band stretches (I have to write his first name that way or the language filter makes a mess of it -- the filter does not approve of the nickname for Richard), especially the set up with the band looped around the elbow and hand in the video below. I do my own variations of this kind of stretching, but I find that the band set up that captures the elbow makes a huge difference (and IMO should be widely used in physical therapy circles, although none of the many physical therapists I've worked with had ever seen it before):
--Various swings with light indian clubs (not necessarily the traditional indian club drills, but mainly ballistic swings in various patterns to explore the range of motion, some of them based on Scott Sonnon's Intu-Flow program, which is on YouTube).
Things that have been counterproductive:
--Any sort of wall slide variation.
--The bodyblade.
--Focusing on "packing the shoulders" when lifting overhead. In my opinion and experience, rigidly keeping the shoulders "down and back" (as "shoulder packing" is commonly taught and implemented) is a recipe for impingement.
Things that have been of marginal benefit:
--I, Y, T, W exercises.
--Scaption.
--Hanging from a bar.
--KB armbar variations.
These drills may be more or less appropriate at different stages of rehab. And I'm not going to detail all the variations within them (and instead of and in addition to them) that I did when my injury was more acute or I was earlier in my surgical rehab. But they are the basics of what has worked for me, and continues to keep my shoulders working well and feeling good.
Some general principles or strategies that I've found helpful:
--If it hurts (during or after), don't do it.
--Drills that are "low threat" and don't force awkward and uncomfortable positions. Train your nervous system to accept comfortable and non-threatening movement and gradually expand the range and/or load (for me, this means NO wall slide drills)
--Drills that get the muscles around the shoulder firing reflexively (such as the David Allen pull-apart series, OS crawling, clubbell and mace swinging).
--Drills that develop strength in the end ranges of movement (such as the Jump Stretch band stretches, and various other contract-relax stretches).
--Drills that move the joint quickly and ballistically through the range of motion, under minimal tension. (such as the light indian club swining mentioned above). I've found that the nervous system will accept moving ballistically under low tension through ranges of motion that are painful with slow motion -- there is less threat response and the nervous system is disinhibited from protectively tensing the muscles, restricting the range of motion and causing sensations of pain.
Finally, through the experience of rehab and training around my injuries, I've developed a much better felt sense of healthy and pain-free shoulder mechanics. Unfortunately it's not something I can really describe or give instructions for, but I definitely think it's helped me avoid further problems.
I also unfortunately can't give any specific advice, but hopefully my experience is helpful in some way.
Good luck.