For about two months now, my gelding Zeus has had a strange lump next to his spine. I noticed it one day after jumping him on a lunge line (teeny jumps-- maybe 6" at most). He didn't give me any signs that he was hurt, but I quit him and let him rest until I could get a chiropractor out. The swelling around it went down after about 3 days. She didn't even know what it was, and just said it was "weird". She adjusted him and he's been riding normally, doesn't seem to bother him while under saddle. It's firm, pea sized, and the skin moves over it so it's not a bite. We were on an easy trail ride last weekend, and he seemed kind of uncomfortable, so we walked back and untacked to see what was up. Sure enough, the swelling was back! It's definitely tender when swollen, his whole back tenses up when feeling it. I'm so confused.
The swelling around it is about 3"