I've had terible acne in the past, and I did every now and then get acne on my penis, even on the head of my penis, that too may be it, perhaps nothing to worry about unless it doesn't go away on it's own.
--Dave.
Can they be spread?
No, not really.
How common are genital warts to form on the head of the penis?
Not common--usually they're on the shaft. It doesn't sound like a wart anyway.
How would pores on your penis head become clogged if this is in fact what it is?
Don't know, but it's pretty common.
Why would a small bump form on your penis head?
Friction, perhaps. Doesn't matter much.
What is the best treatment assuming it is not a wart?
Nothing.
If the bump persists, please show it to a doctor.
Best.
Dr. Rockoff