I Have A Small Place Come Up On My Back

I have a small place come up on my back the size of a nickel and I'm not sure what it is my wife said it looks like ring worm but I'm not sure also after I found that I found two dots that came up on the back of my neck but they are not pimples and can not b popped and have no head on them and the other place I just found tonight is under my right left butt cheek and it's a line. I started to itch and when I scratched it hurt at first I thought it was a scratch or something that I didn't realize I had but it seems more like it's under my skin. Could anyone help me out on what this and if it's any reason to go to the ER