Kevin, I hope you're wearing 100% cotton underwear. Organic cotton if possible. Any synthetics don't allow free movement of air. Dyes can also irritate skin so wear white or preferably unbleached...and it's better to wear boxers as men who wear briefs have a lower sperm count. Also, pick up some good laundry soap on your trip to whole foods...
And make sure your underwear's not too tight!
I hope your problem with that area is as simple as this... :)