What Causes Pimple On The Glans Of Penis?

I have these small pimple like objects on the glans of my penus. It is not around the rim of my penis (like I've seen through pictures via the internet) but more on the head. I am uncircumsized and can be seen when the foreskin is pulled back. Additionally the tip (when the forskin is not pulled back) itches from time to time. I am not sure if it is due to cleanliness or some form of STD. I do want to add that I frequently pull the foreskin back and bath but did switch soaps about a week ago and is not sure if it is something serious or an allergic reaction to the soap. The pimples remind me of a rash look and not neatly lined up like PPP.