I didn't know if I should start a new thread or just add it hear. I hurt my back doing lunges, lost my balance, and when I straightened up, felt that "twang" in my low back. It hurt right there where the triangular bone is at the base of the spine. I went for several months with low back pain, getting massages, hot packs, low back exercies, stretching, etc. I couldn't heal my back. I finally found this book as I was surfing the web for some sort of help,
http://www.triggerpointbook.com/ , and as it turned out, the back pain was actually coming from a small knot in my glute (hence the problem occuring during the lunge). Here's a link to where my pain was and where the trigger point was that was causing the problem
http://www.triggerpointbook.com/backpain.htm Anyway, I treated it with a tennis ball and reduced the pain after the first self applied massage by about 50%. After a week or a week and a half, I was totally pain free.
THIS IS A GREAT BOOK, I HIGHLY RECOMMEND IT TO EVERYONE! GO GET IT!
Read some of the stuff on the website. I think this explains why 85% of low back pain is unexplained. It doesn't actually come from the back. That's why you aggravate your low back when you do squats, not because you're compressing it, but because your using your glutes and aggrevating that muscle.
Anyway, it's helped so many friends of mine, stuff from low back pain, to carpel tunnel, to knee pain, to headaches. Get the book!