Sounds like more of an ELO thing. Maybe counter pick with someone who has a silence? (Cho/Garen)
Garen is a really hard matchup for Riven. Riven has the lowest hp/10 in the game and Garen's passive gives him one of, if not the highest hp regens in the game apart from mundo ult. A silence will force Riven to back off/will forget up her combo and will silence her until her Q goes back on cooldown, greatly reducing her trading power. That, and the fact that Garen gets bonus resists from his W active and passive and he has a pretty high health/level make Garen really super annoying for me when I play Riven. Cho is a little easier to face because outside of his silence, he's VERY easy to duel. He has no mobility and is very squishy early on, which makes it very easy to kill him early, and as you know, a riven with a couple early kills can snowball into an unstoppable monster.