Shoulder Pain

[5hout]

Recently (since too aggressively getting back at it) I've had left shoulder pain/tenderness when lifting arm directly overhead and some pain when sleeping. The pain is directly on the interior (toward neck) side of the AC joint. Painful spot is about the size of a quarter with the far edge located on the AC joint and the rest of the coin laid in towards my neck along clavicle. There is no apparent tear/looseness in any parts of the shoulder via touch/pushing or motion. There was no instance of intense pain or injury. A couple of, tbf, great workouts and then pain settling in after.

Pain only occurs on overhead pressing motions. Resting it for a bit over 1 week with stretching until before pain occurs, NSAID, heat and doing only non-painful lifting has been somewhat effective. I'd say day 1 I had maybe 85% ROM. Now I can do (in the air at least) wide grip OHP motions pain free. I could always bench/do pushups without pain.

To me this looks like pretty classic tendinitis. Most likely some AC/CC tendinitis/joint inflammation. Based on location of pain it seems less likely to be rotator cuff, but certainly could be 2 things at once/compensation issue.

Questions:

1: Do I seem to be missing something that indicates doctor trip over just rest/stretch/non-painful ROM exercises?
2: I found a position last night (lying on my side, relaxed, where I could use my good arm to help move my gimpy arm through full ROM without any pain and it felt incredible so long as I left the muscles of gimpy arm/shoulder completely relaxed. If I tensed them during the motion it hurt. This feels so good I almost can't stop doing it. Is this significant in any way?
3: More generally: Am I missing something completely obvious to more experienced/people with actual knowledge not garnered by reading lots of Exodus/SS/T-Nation/podcasts?

[Hardartery]

There is very likely not just one thing going on. You could have a strain or even partial tear of the supraspinatus and additionally you could have other strains/partial tears/tears in the surrounding tissues and you definitely will have inflammation inhibiting stuff. You also may havr simply torn a nerve or partially torn it. No way to know over the webs for sure.

[5hout]

This was helpful, in that I def had some "I only know a few things so it must be one of those things" logical fallacy going on.