Okay, so this actually isn't a current problem. This is just something I was thinking about.
Shantee is an arabian mare I had bought as a project several years ago. Well, the entire thing about buying was fishy. It was like the owner was begging us to take her. We got her free in the end, so I guess it wasn't technically "Bought"
The way I saw it at the time was "No harm in trying. She's beautiful and sweet."
Which she was. On the ground she was an ANGEL. Came up and loved on you, followed you around but was VERY respectful. I taught her all the lunge cues, ground driving, even some little tricks like bowing and rearing.
But why did I have all the time to do that? Because the day I brought her home her left shoulder swelled up to the size of a watermelon. So groundwork was all I was okay with doing. She could still move fine. I never worked her past walking circles on the line, and then the swelling went down and I did trot/lope
But then it swelled up again, just after it had gone down.
We ended up just selling her as a pasture companion for a little girl who couldn't ride but wanted something to love on. She's never been impaired by the shoulder at all.
So what could have been wrong with it? It felt cool, but squishy like it just had swelling. There WERE occasions on the first day of the swelling where it would be warmer than normal but it was never pulsing hot.