I took my last shot in my left shoulder last thursday. On sunday I start to have a bump form on the bottom point of my shoulder and it is very painful and it is as hard as a rock when I touch it. It is now wednesday and it is still there, I took my temperature and it is 97.5 so I don't have a fever. Where the spot is the skin looks a bit red and blue and the size is as big as a golfball which is under the skin and sticks out a bit. What the heck do you guys think it is? do you think i could have an abscess because I'm the most sterile person there is so there is no way I injected any bacteria or germs or anything of that nature. need help, thanks.