Any time you notice something such as new mass or growth especially around a surgical site, you should attention from a qualified health care professional. In this case, the best physician to contact is the urologist
that performed your vasectomy
. Unfortunately, physical findings are not possible to diagnose through a description. However, I should be able to give you a few possibilities. During a vasectomy, the vas deferens (the tube that delivers sperm to the semen) is cut preventing sperm from being a part of the ejaculate. The vas deferens can be cut in several different places. If the bump that you feel is near your incision site, then it may be some scare tissue associated with the surgery. If it is not close to the incision site, it may be the cut end of the vas deferens that as retracted away from the testicle after the surgery. Then again, this bump may be completely unrelated to you surgery at all. I suggest that you schedule an appointment with the urologist that performed your vasectomy. He or she cant take a look at your bump near the area of of the surgery and determine if it is something that needs further investigation. At the very least, your doctor
will give you reassurance that what you feel is normal. Good luck.