First, go to a doctor. You cannot diagnose yourself, as there are many problems that cause similar symptoms. If you're uncomfortable because you have a female doctor, switch to a male. If you're uncomfortable about telling your parents, tell the one you're most comfortable with. They're not going to judge you for something that's not in your control, they're not going to ask to see and prod at you, they just want you to be healthy. So GO TO A DOCTOR.
Second, yes a common percentage of males have varicoceles, but most do not have any symptoms.
To your numbered questions...
1. No, it will not affect your ability to have sex, unless you are currently in pain. Then you will not likely want to.
2. It can cause infertility, but it is reversed when surgery is done to correct the varicocele.
3. Same as the second question.
You have to go to the doctor and make sure you don't have anything else first of all. Even if you have a varicocele, it does not mean that necessarily is what is causing the pain.
If you do have a varicocele, the standard way to fix it is surgery. A second, less known option (so ask your doctor about it if he doesnt bring it up, or find one who knows about it so you can learn all of your options) is embolization where a coil is inserted into the offending vein.
A third possible way is through natural medicine, diet, etc. I have a varicocele and was going to attempt fixing it this way, but another health condition came up which is more important. In the interest of not taking too many supplements, I'm only taking care of one at the time. However, my varicocele hasn't bothered me much for the last year and when it does it's very temporary. I'd tell you how you might fix it, but I don't want you trying something that A.) Would take several months to work, B.) Might not work, and most of all C.) Lead you to try this remedy as opposed to going to the doctor, ruling out other possible conditions, and talking to him about options.
