Originally Posted by Kayty
No not all mares, but there are a handfull out there that most certainly do!! I had a WB mare that got it something shocking, you couldn't even put a rug on her when she was in season she was super sensitive. Had the vet to her and he said she's certainly getting ovarien pain, I had to have her on hormone medication to settle it down.
I routinely palpate 15+ mares a day during breeding season and believe me, they can be extremely tender when ovulating- thank god for kick panels on stocks. If Lacey were to have an ovarian adhesion (not uncommon in older gals) it could make it even more painful. But she really shouldn't be cycling right now, so that is kind of less likely. You haven't mentioned any aggressive behavior, but sometimes mares get tumors in their ovaries which can be quite painful and cause changes in behavior. They are usually a lot slower to show up though.
Basically I'm not sure what is up either but if it were me, I'd try to check her tonight (or have someone at the barn check her). I do think it could be colic, but it is weird that she was fine while you rode. Let us know what you find out. If she still hurts tomorrow, call the vet!