I have been experiencing pain in my shoulder for 3 months now. It seems to have started after I started doing push-ups a lot without proper preparation.

This pain is not constant, it is provoked by certain movements, for example, when I put it behind my back, or when I make bottom-up movements against resistance while pressed to my body, sometimes this is accompanied by a click.
My right shoulder also sometimes clicks, but I do not experience any problems or pain with it.

A month ago, I went to an orthopedist for the first time and had an MRI. The MRI showed signs of suprastine tendonopathy and minimal synovitis. The doctor prescribed a course of anti-inflammatory drugs.

This did not give a noticeable effect and I recently went for an ultrasound of the shoulder joint. Minimal tendonitis without inflammation was detected, which, according to the ultrasound specialist, does not reflect my complaints.

I try to lead an active lifestyle as much as possible, but at the same time not to put too much strain on my shoulder - I go to the pool,
even do 5-6 pull-ups (this is no more than before the shoulder injury).
All this activity can happen without pain, and then during a shower I put my hand behind my back - and here it is - a click and pain...

Tell me guys, has anyone had something similar?
I am at a loss what other tests to do and which doctor to go to, what could it even be if the ultrasound and MRI show minimal or no changes?

P.S.:
Also, my left shoulder seems to look a little smaller and the muscles aren't as spongy as the right one. Does this look suspicious from the photo?

3 month pain without explanation