About 3 weeks ago my left testical swelled up about 2x the size of the right, and I took a blood std test at the docs, they said everything checked out. But the testi is still a little biger than the other and there's a lump I guess u can say in the vein of the testical its self what do you think it is I'm freeking out about it.

Need to know your age. Is it painful? Does the swelling go down with changes in position, like when you are lying down? (hernia). Is the testicle rockhard? Swelling can be caused by numerous entities. Infection of the sac where your sperm is stored (Epididymis) is one. Testicular torsion is an emergency. It means that the testicle is twisted on itself and that requires immediate attention, otherwise the blood supply to the testicle maybe affected. Every lump in the testicle MUST be investigated. Cancer is also in the list, as is STD. Fluid in the testicle can give you swelling as well (Hydrocele). Veins near the testicle can be prominent (Varicocle). As you can see, there are many causes and you did the right thing by being seen by a medical professional. A careful follow-up would be needed. The terms I used in this reply can be accessed through Goggle. Hope this helps. By the way, I am a health care professional. Joey G