Took a short ride today. By the 6 km mark I noticed a bit of mid to lower back pain. I wasn't even riding in the drops, but on the flats of my bars.

Have I been riding with the bars too low/saddle too high? I feel like the stroke of my leg is comfortable, and I'm not sure if I want to lower my saddle anymore. But am I right in diagnosing the root of my pain?