By the way, I think that's OUTSTANDING support from that owner. Of course, maybe knowing that you are relatively new to this, he's just trying to save himself some extra work from a botched repair job , but I think he has an amazing sense of responsibility towards his customer base there.

As far as the back thing, well, I'm not a doctor, but I did stay at a Holiday Inn Express last night, so I'll theorize.

When leaning over on your own (not on the bike) you are using your back EXTENSIVELY to keep your balance, and keep everything together the way it should be. Even when you do something as simple as tieing your shoes. However, when you lean forward on your bike to the handlebars, your butt is balanced and supported the entire time by your saddle, and you torso is supported by your arms. In other words, though you are leaning, the bike is acting a bit like a second skeleton if you will, and you are perched upon it.

I would imagine, if you were to lean forward and pedal while standing on the pedals (I.e. supporting all your own weight) you may have found a way to hurt your back somewhat worse than it already was.

But, then again, I'm not a doctor.