What Causes Pus Filled Lumps On The Scrotum?

So I ve had these sort of pimple like things on the back my scrotem for a while now and I assumed that they would go away but the never did. These bumps have been around for longer than a year but the have never irritated me. I m 18 and I ve never had sex so I doubt its any sort of Sti. The bumps themselves look kinda like pimples but are very difficult to pop, they seem to be filled with puss and the skin surrounding them is quite red. There in a big group of them at the back of my scrotum surrounding what kind of looks like a seam in my scrotum. I don t think they re harmful but they re really ugly so I d really like to know what they are and how to get rid of them.