Thanks all -- good advice (except for sitting down!!!!). Will see the Doc for sure -- just thought some of you might have been up against this syndrome before and had a quick fix.

It just made me curious that I was doing something differently -- we jam at festivals for 4-6 hour stints, standing, and have had no trouble.

Now suddenly I can't get through more than 5-6 songs before this annoying pain sets in.

But as you have universally pointed out, it's a matter for the medical pros - MD, orthopedic, osteopathic, or chiropractic -- no hang-ups there.

Thanks again.