I have a painful lump on my scrotum, just at the base of my penis. I think its an ingrown hair or a large pimple, but im not 100% positive. Is there something more sinister that I should worry about? There are no other symptoms present. Im 29 years old and married, with no reason to suspect an std. I dont have a picture to upload, but it just looks like a red lump roughly the size of a kidney bean. it is freely moveable, and it travels from the top of the scrotum to the bottom of the base of my penis when im erect. Its only particularly painful when I poke or squeeze it. I have no reason to suspect an STD, and Im 29 years old with no other health concerns, sans being overweight.