Hi, I have been wondering about my penis lately. When I am done masturbating there is this bump or lump on the right side of my shaft. I really don't know what it is. It kind of feels like a ball of nerves and it's about the size of a dilated pupil. I am worried about it.
What you have is called Peyronie's Disease. Your penis has three inflatable tubes, two on top and one on the bottom that produce your erections. The tubes aren't empty space, they are more like sponges. What happens in some men is that scar tissue forms in a spot of one of the tubes. The scar tissue can cause a bump on one side of the penis during erections.
The scar tissue can take up to a year and a half to form. During that time up to 2/3 of the men with this problem experience discomfort or even pain that then fades after a few months. About 40% of men with Peyronie's Disease develop a bend in their penis because the scar tissue blocks the flow of blood and keeps the tubes in the penis from inflating evenly. It is only in the cases where there is a severe bend that corrective surgery is needed.
There are several suspected causes of Peyronie's Disease. The most common one is where the penis is forced to bend while erect. High blood pressure, hardening of the arteries, or diabetes are also know to cause scar tissue in the penis.
If the lump increases in size rapidly, it could be something else. You would need to see a doctor to make sure. You should see a urologist anyway. Since it is just forming, there are things a doctor can do to lessen the discomfort and perhaps keep a bend from developing.
Source for additional information: Peyronie's Disease