Ya. Slow moving debris making scratches on the hull. Really, if the hull wasn't built to withstand slow moving impacts from space objects like that, what makes it fit for space conditions?
And the Enterprise would have had the shields up immediately after they saw the debris and went to red alert anyway. Kirk's storming into the bridge was pretty much unneccessary. They had a full minute before Nero detected them, and the shields were apparently not protecting them from the debris.
Not completely. They wouldn't...
It has been established on numerous occasions that shields only provide complete protection against damage up to a certain threshold. Beyond that threshold, shields provide INCOMPLETE protection, allowing a small portion of the damage through to the hull. Those of us who play Star Trek based wargames call this the Leaky Shields Rule...