I know I should go to the doctor, but what could this be?

About a year and a half ago I noticed a little somewhat itchy bump on my upper arm, about the size of a bug bit, and in fact it did have two very small “puncture” holes. It stopped itching after a week but the bump remained, at this point it looked like a pimple that never fully formed. Not to be gross but I did try “popping” it and there was nothing, so I ignored it. Over the past year it has grown in size under my skins surface. It is currently about the size of a dime in circumference and feels like its about as thick as a small marshmallow. Now it doesn’t itch anymore, but if its touched it hurts. If its moved, like pushed on from the side it feels like its attached to muscle and is being ripped off of it. It had stopped growing for about 6 months and last week I noticed that there is another section starting to grown on it, mind you this is all under the surface of my skin.

I have a few friends and friends parents that work in the medical field i.e. are nurses or people like that that tell me they think its just a benign cyst. If it is would it still grow and hurt when touched and sometimes hurt when not touched?

The reason I haven’t gone to the doctors is because frankly I dont have the money or insurance, and no I cant afford insurance either.

So what do you think it could be? Any ideas are helpful.
Please, serious answers only.