This could be an inflamed hair follicle. Folliculitis is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin.
Folliculitis starts when hair follicles are damaged by friction from clothing, blockage of the follicle, shaving. In most cases of folliculitis, the damaged follicles are then infected with the bacteria Staphylococcus (staph). The tiny nicks/abrasions caused by shaving is sufficient to allow the entry of the bacterium into the follicle.
It is seen as pimples or pustules located around a hair follicle typically occuring on neck, axilla, or groin area or may be present as genital lesions.
You can apply an antiseptic ointment on it, which is adequate or you could try topical antibiotics such as mupirocin or neomycin containing ointment.
It should resolve on its own without any application in a week's time.
Its been this size for about a week already and seems to be staying the same size. It has not gotten any small or bigger, its just a hard type feeling bump that is located under the skin, It never busted or ozed any puss out of it also.
I have had several of these develop over the years, one particularly annoying one on the back of my head, and a new one developing within the last few days behind my left ear lobe where only the finest peach fuzz type hair has ever grown. Like yours, they are a little painful when they first develop and then simply stop hurting and become a new but permanent feature. The one on my head I've had for at least a year and a half, with no change in size. I have lanced it, a quarter inch into it at the lower facing point of the oval, and never any form of discharge, not even blood, from the puncture. This leads me to believe that it is not a puss-generating infection like Staph. Again, the object formed and stopped hurting after a a few days and has never changed in side. It has about a half inch diameter of total movement under the skin on my head. The one behind my earlobe seems rooted in the muscle tissue and will not move at all.