Seems to be more of a joint, spinal thing rather than an erector problem.
Definitely the occasional acute pain - not a chronic aching.
In the few weeks between when I originally submitted this question and now, it seems to have “healed”, only bothering me at random.
I do appreciate the reply and willingness to help me solve an issue, though. Seriously, man, it means a lot.
I ended up just figuring out what hurt and avoided that for a few weeks. Now it seems to be okay, but I’m still being careful and meticulous when it comes to my form.