So I've been following a lot of your writings recently regarding some high rep work, not to mention your book which has tons of great info in there. Anyway, a quick anecdote: my shoulders had been hurting a lot after overhead pressing. Kind of a tendonitis hurt rather than muscle pain or nerve bullshit or whatever. So one day, after pressing I picked up a pair of ten pound dumbbells and busted out a set of like 40 reps and I'll be damned if the pain almost instantly completely stopped. So for the next several weeks I've been busting out high rep sets for any joints that hurt and it fucking works! No more shaky arms (not in the good way, anyway) after training. If left to my own devices, I probably would have fucked around for months just hurting myself worse and worse. So thanks a lot man, if it wasn't for some of your random dropping of knowledge I'd still be hurting.
So if you have been having some particular joint or muscular pain for certain areas, chronically, find an easy movement that you can do to get the ultra high reps in for it. The key here is to stay LIGHT. You are not using these sets for progressive overload. You are using them to flush insane amounts of blood through the tissue for healing, prehab, and hypertrophy. The mental toughness required to keep going also isn't exactly a bad thing to teach you.
While I am a firm believer in progressive overload on the big stuff, the small stuff can be used quite effectively with light reps and high rep sets. Use your big movements for what they are intended for. Moving weight through space. Everything else should be about making the muscles work. The lighter you go from a loading progression on those movements, the more apt you are to make the muscles work rather than move the weight. This means you will utilize the movements far more effectively for the muscles intended.
This is smart training.
Don't be a dumbass.