pimple sized bumps that are unpopable, itchy, sore?

I have had these small pimple sized bumps that at first glance look like large pimples, but they are unpopable, sometimes itchy and sore. More keep popping up, I got the first one around four years ago just thinking it was acne and it never went away, and over the years more have shown up, I now have nine, mostly concentrated on my right shoulder and I have a couple on my chest, I now have one on the middle of my back, please help I have no idea what they are, I am 19 and hate having to hide my shoulders. I don't have health insurance and don't know what to do, if you have anything that can help please let me know, thank you.