Maybe it's a cyst, or a scab. See a doctor.

http://lastmed.com

It actually sounds exactly like Hemorrhoids. You could try an over the counter relief ointment and see if it goes away with this. If not, proceed to a physician.

those are more and likely hemorroids. there are internal hemorroids and then there are external hemorroids which align around the lining of the anus. hemorroids can occur at any age due to strain, as well as anal sex.
sadly, unless you're pregnant, which I highly doubt unless listed...they will not go away. Unless they are extremely painful, you get surgery to remove them...but other than that, they're not that big of a deal.

This is more than likely a hemmorhoid. You are not too young to get them. My husband is 24 and has had one already. If you strain when you go to the bathroom that can greatly contribute to it. They have creams with applicator so you can insert it into your rectum. If it doesn't go away within a few weeks you may have to see a proctologist to have it removed. Internal hemmorhoids are the worst kind.

u could have "anal warts" too for that matter, trouble is u could get them from visiting the doctor if u don't have them already, make sure they clean their tools before they go probing around in there, gl w/ that.
i'm a five year sex virgin, never gay and suddenly have a lifelong "STD" called "anal warts" showing up 6 months after having a colonoscopy, go figure?


btw I've had hemorrhoid's since I was a teenager so your difinitely not to young for that.