Where there's hair, there's joy and the possibility of pimples. The hair follicle is the same one through which sebum (which I don't know) comes out. Sebum is a natural lubricant that protects the skin. But when there's an excess, or it mixes with too many dead skin cells and bacteria, the pore gets clogged and a pimple appears. Nothing personal, just chemistry, oil, and a bit of skin chaos.
 
And do you know what two situations don't exactly help keep body pimples away...?
Well, being a guy and playing sports. There you have it: