If you're new to riding you will have a little soreness to work through no matter what, but as Inspmark said, a good pair of riding shorts (or a couple) is a very good investment for your riding enjoyment. I've tried the cheaper $25-$30 pairs and there's no comparison between them and a nice pair of $60-$80 shorts. It's well worth the extra money if you're going to do any serious riding.
Cycling... If you're not having fun, you're doing it wrong.