So I got my 8 year old OTTB last October and she seemed fine. She was on the track until she was 6 so we were just working out some flat work issues. Now she's come a far ways and have started jumping up to 3 feet. I was noticing she wasn't being herself. Very laggy and zombieish, and wouldn't try or get worked up about jumping. She would usually run to the jump and do a huge over jump without me even needing to add leg, but she started running out, refused once, and often knocks the rail. I'm giving her a ton of leg too… The vet came out and we were lunging her in only her halter and she would cross fire at the canter, and kept swapping leads in the back. She did the tail pulling test and she was worried that she could easily knock Bella off balance and stuff. Bella was also very sore it seemed in the back of her back legs by her butt, and would flinch and pick up her leg if you ran your fingers in that area. The vet initially thought it was the EPM parasite in her spine, making it so she couldn't feel her back legs, but the test came out negative. Now she thinks it's the EPSM sugar instead of fat thing, but many people at my barn disagree because her food isn't that sugary. Also, that same vet diagnosed many horses at the barn with EPSM and none of them actually had it… I rode Bella again for the first time in a while, and she seems like she's more herself, but we only did flatwork, and it was on the track where she is always energetic and crazy. I also tried touching the tender spot on her legs and she didn't seem to care. I don't really know where to go from here. I first started noticing she wasn't her self a couple months ago - a tiny little thing was off, I thought maybe she was just starting to calm down - but it started building up recently and really being noticeable! Could her saddle not be fitting right? Her back has changed 4 times since I got her, and it might make sense because she would try to nip my toes when I was getting on, even though I don't jab her, but that has slowed down a lot. I know this is a long message, but I don't know a whole lot about specific horse things I guess and I'm just really confused.