I feel your pain, I experienced this incredibly severe itching for 6 months until finally I was diagnosed with genital warts. Many people experience itching, but a lot of doctors say it isn't to do with GW. I think it is. The itching was so intense sometimes, I didn't want to leave the house, because I knew I couldn't scratch. Luckily for me though, after I used aldara and the warts went... so did the itching. The itching was twice as intense when I was on the treatment, but then one day it was gone. Maybe for you it will just disapear too.
When I was experiencing the itching though, I used non perfumed moisturizers especially for itch relief which helped a lot. If you shave it could be something to do with that, or it might be a fungal infection or a different STD. The only thing you can do, is use lotion, wear baggy boxers and trousers and look for some itch releif tablets. Maybe your allergic to the treatment or someting else down there?
Heres a website which might benefit you..