Just noticed this on Schmidt today. Must have popped up over the last couple days because I trimmed hooves a couple days ago and didn't notice it. We hiked today and he seems to be in great spirit. Might be kinda hard to tell from the pic, but it is a dark bump. Looks like a blood blister?
Thats not a injection site. A couple inches lower is a typical CL location. Although they can be any size, they are typically bigger then that. Worth keeping an eye on though. But if I had to guess, Id say there is probably a sliver in there. Do they eat from a wooden feeder by chance?
My yak used to leave lumps on the goats from time to time (upward sweeping horns are more effective). Just a blood blister. They went away. That one on your goat looks like it wants to pop-- The hair has fallen out. Generally harmless though.
Thats front of shoulder. Typical site is behind the leg on the arm pit. Granted thats not a great area for goats who need to wear saddles. So could be a injection site.