Flack Staff wrote:
It could be a SI joint problem or a slight twist of your pelvis. does your PSIS feel like its sticking out further than your other one. Lie on a hard floor with yout knees pulled up and you may feel this. If so find a good chiropractor and get your hips and SI joint into normal alignment. If your not in proper alignment and you have a pelvic flare or tilt, all the therapy and core work will be useless.
I'm pretty sure I had the same thing, and really had a tough time isolating it to stretch. For awhile, I was sure it had to be something other than muscular since I couldn't figure out a way to stretch it, even after a physical therapist had shown me the correct stretch for that area. Turns out, I had to play around a bit with the stretch before I figured it out, and since I've had no problems.
You may be doing this already, but if you can't feel it stretch you may have to vary it a bit. Lay on your back. Bring your left knee up so that you can place you left foot on your quad immediately above the knee cap. Use your right hand to pull your left knee down to the floor on the right side of your body while keeping your foot on the quad. You should try to keep your left hip from rolling to the right so that the back stretches, but that is pretty tough to pull off alone (if you have a partner, have them hold your left hip in place while you do this. That is supposed to stretch the area of the back you are talking about, but it never quite worked for me. What I had to do was once I pulled the left knee to near the floor on my right side, I then started to pull the left up towards my right shoulder. When I did that, I could really feel my SI joint stretch out, and all those little muscles tugged just right. No problems since.