Update - it quieted down, so I did a CX race on the weekend. I worked hard, but used my gears a lot, and I couldn't feel any issue during or immediately after. However, I think the 1.5 hour drive home was not the best, and the groin, and especially the muscle that runs from groin to under my ribs on the right is really tight and sore. It doesn't really like me sitting down, which is a bit annoying!
I'm gonna skip the CX this weekend (also involves a 3 hour round trip in the car) and ride gently on the turbo and stretch/roller like crazy and see how it goes. Probably start PT again next week, and see if they have any bright ideas.