A couple of rides ago I started getting this lower back pain. Today, I feel a pain that seems like it goes around my entire pelvic bone. The lower back is sore right where the hip becomes the back. And the front of my hips are sore right where thigh ends. There's even some soreness on the sides of the hips. The pain in the front of the hip feels alot like impact injury I got once from jogging in old, beat up sneakers. I didn't expect to feel that from riding. It's weird.
Recently I started moving the handle bars and seat around to lessen shoulder pain. (No more pain there, anyways. ) One effect of this was to end up with my knee about an inch or two behind the BB when the pedal's at 3 o'clock, and also I'm leaning forward a little more on the bike. I was wondering if this position would stress different muscles than I had been using, and if that was causing the pain.
Today, after about an hour my back just got tired, and it was hard to pedal. Almost like most of the pedallling effort needed to come from the back muscles. If it's just sore muscles due to a new position, then I'll just put up with the pain and figure it'll go away.