[Phaedrus49er]

I'd suggest getting a good foam roller and start using that (I linked a "why" and "how" article; grab the actual roller from PerformBetter.com or any other site advertised on this forum). You also mention that you've knowingly used poor form. Stop it *slap* Good call on lightening the loads. Swallow your pride for a bit while you get the mechanics in shape (I know I've had to do that myself).

As for the localized pain, it could be a number of things, but I'm willing to bet it's a combination of weak glutes and tight hamstrings (I used to get similar pains). I'm sure others will chime in on exercises, but lunges and split squats should be a good start once you address the pain issues. Go easy at first in case there is an inherent weakness in the glutes--you don't want to get hurt even worse. (All this assumes it's strictly muscular pain as opposed to spinal of any sort. Also, I bear no responsibility for the advice given above )