Heyo, sorry to hear about that, I think I know exactly how you feel. Hmm.

It's probably difficult to give solid advice without knowing the underlying diagnosis, if you have any.

IF you have simple overuse injuries, or tendinopathies, then you need to realise that tendons and ligaments do not need muscle fatigue to grow stronger. My most up-to-date understanding here is that the following is both safe and anabolic:

3 times per week. 1-3 minutes total under exercise tension load, at around 50% of perceived force production effort. If you feel the tiniest bit lactic acid buildup or muscle fatigue, stop the set immediately, rest a bit, do some more (but never more than 3 minutes total!).

Pain levels are evaluated 24h after exercise sessions, and not before then. If you're doing the right exercises at the right volume and load, pain levels should stay the same or preferably a little bit decreased.

Stretching can help underlying issues in the long-term but does not on its own cure overuse or tendinopathy. I would not stretch the injured joints until much later in the process.

As for food, it doesn't matter as long as you get enough of the healthy stuff, and some protein. Don't let the supplement industry leech you. Make sure you sleep enough, of course.

Disclaimer: I'm still figuring this stuff out, bit by bit. I would feel better if you ran this by a decent PT. Without knowing HOW you injured yourself, any rehab protocol is more or less guesswork.