I've reached a point where I think I'm encountering an issue.
In 2016 I had a slap tear in my left shoulder that required surgery. As a result the suction in my left shoulder joint is compromised and pulling exercises are straining that. It creates a feeling of instability and feels like the ball joint wants to separate from the socket again.
In particular this is affecting back day due to back day being so pull oriented. So I'm at a point where I've lowered the weight and am focusing on slow form. I doubt I'll go any higher than this on back days for quite some time.
Days like this aren't a bad thing though, it's good to know your limits and with an injury there are some body groups that simply have to be worked slower/lighter to compensate. It's a little disappointing to see such an early weight plateau but safety comes first.
Once upon a time at the age of 18 I was rear ended by a car going 65mph while I was at a stand still waiting to turn. Shattered my left collar bone and messed up my shoulder. I'm now nearly half an inch shorter from shoulder to neck on my left side and have a horn protruding from my skin where the doctors didn't set the bone. Then, I had all kinds of spinal issues such as the rib heads in my back constantly slipping out of joint whenever I'd pull on or lift anything too heavy or even sit or lay the wrong way. Sometimes it would get so painful it was very hard to breath so my wife would always be popping them in.
I'm 34 now. Through careful and consistent recovery exercises over several years I was able to get to where I am now, competing against and training with professional arm wrestlers. If you think that's something trivial, please go find one to wrestle with and then get back to me. Anyway, before my road to recovery, I'd let my testosterone fuel my fear of missing time and what that meant for my max potential. This lead to me going far heavier than I needed to which lead to so, so many more set backs than I would have had if I'd just taken it slow.
The things that helped me the most where,
Rings - Amazing for your stabilizer muscles. All kinds of exercises from hangs to sit backs. I started from the beginning of every exercise as if I where a child. So I'd start at the bottom of the form of a pull up for example. I'd stay there for months before moving on, all the way to using bands before I did a full pullup with perfect form.
Isometrics - I believe isometrics help build the mind muscle connection to the muscle chain around a problem area. So, for instance, say my ribs are slipping out because the tendons around them are weak or too stretched or inflamed etc. Whatever the reason, I believe you can stabilize that joint by building up the stabilizer muscles around it. But sometimes you can't even feel those activate over a normal short rep. Isometrics help activate the entire chain in that area as the main muscle fatigues and the stabilizers slowly activate and take over, getting a workout. This is why I believe it's best done by starting with low weight and longer holds since your underlying tendons and stabilizers might be weak and once the main muscle exhausts you don't want to be putting all that weight on them.
Chiropractor - One that takes Xrays and uses nerve reading instruments. Say what you want, but while it might be hard to find a good one, once you do you'll understand. I had a nearly flat spine and they straightened it.
Wim Hof - Cold training helped me contain all the inflammation and sped up recovery immensely.
But honestly, nothing made me feel more put together than when I really started to focus on growing my tendons by lowering weight and switching to 3 sets of 100 wherever I could as well as isometrics. Nothing comes close to how fast I recover now and how much of a beating I can give my body and feel great afterwards. I feel more flexible than ever and can even contort myself in bed or on a couch where before this would lead to bones coming out of joint and tendons getting super tight and tense.
I'm now stronger than I ever was and feel like a teen again. I can now do strength based exercises just fine. The only wall is going to be my lower back but even that is coming along as I do my standing crunches for high reps.
Anyway, my point is, if your shoulder seems like it's wanting to come out of joint, I'd guess it's because some tendons are either detached or too stretched out. It's way harder to shorten a tendon than it is to stretch it so just keep that in mind. But IMO switching to a workout that grows your tendons might be something to consider. And like
@DonDonDonPata already mentioned, the isometric stuff will help stabilize that area in the meantime, like I was saying above.