My medical team is fantastic! Thanks guys!!

Sounds like ultimately an imbalance/weakness issue (which never manifest on the bike before) brought up by too much too soon after my 6 month hiatus. Well, shoot. My lungs are really good this year!!

Maybe I will back off the mileage a bit. Work on the stretching. Try my orthotics. See if I can get to a sports medical PT or something. Drink good wine. (Wait - that's not one of the suggestions??)