Thanks for the reply. And I thought I'd give an update.

The "void" feeling has pretty much disappeared, but it's been replaced with an equally uncomfortable feeling. I pride myself on having very loose hamstrings. I stretch them ever night and have done so for years. But yesterday I felt a little jolt in my glute and then my right hamstring (the same side as my SI issue) suddenly tightened up.

It's been extremely tight for over 24 hours now. I think this is related to the SI joint, because just 36 hours ago my hamstring was as loose as could be. I stretch it now and it does no good, it just stays tight.

I saw another chiro today and, truthfully, he didn't spend much time with me. I felt like I was being rushed actually. However, he adjusted me and explained that my hamstring isn't actually tight or in spasm -- it's being pulled by an out of place SI joint and that makes it feel tight.

He adjusted me and I got maybe another inch or so of movement back in the hamstring. He then said that for two days don't do any exercises -- even core stuff -- and just do two simple stretches: single knee to chest and both knees to chest. He said these will help open the SI joint. He also said he wants to see me 2x a week and he was confident that by Christmas Eve (about 2 weeks away) I should be feeling fine.

My question is, do you guys agree with his assessment? And I should have asked him but I forgot to: if my SI is out and is pulling on my hamstring, does that mean my SI joint is rotated up or down?

Thanks for any replies.