Let me start off by mentioning that about 3 weeks ago (or so) I noticed a small red lump on my scrotum, not attached to anything. I was initially pretty worried but then after a couple hours it disappeared. I thought maybe I scratched in that area or something causing the red lump. Anyways, today I noticed the same red lump again on my scrotum but in a slightly different location. I'm not sure what this could be but I haven't had any sexual contact recently so I'm confident it's not related to STDs. Yet again, after about an hour or two it disappeared. Aside from this, I have had a small lump inside my scrotum sack near the base of my penis for years now. When I put the two together I become very worried, yet the red lump disappears so quickly and is completely painless, so I'm not sure if I'm overreacting or if there is a real problem. Is this harmless? Serious? Should I do something about this? Thanks.