In all my years of reviewing office chairs, I've only given four chairs a perfect 5-star rating. The Sihoo M18, now available for just $139.99 on Amazon, down from $169.99. So what makes this chair one of the best office chairs for back pain? The lumbar support adjusts both vertically and in tension, letting you dial in precise lower back support for your spine's specific curve. The result is a chair that looks surprisingly sophisticated, with thoughtful details like the grey mesh framed by black bezels and color-matched lumbar support covering.