my issue with the background (i am including the rail as such because they visually join) is that the top half and the bottom half are pulling in different directions.
it isnt a matter of leading lines, because they dont lead directly to the subject. the railing OR the roof section(?) would have been fine, but together they pull the eyes in all directions.
in a shot like this (and im certainly not an expert so take this as just some idiots opinion) the eye should be led to the model. in this shot though, everything else in the picture leads the eye away from the model, or competes with her for attention.
the B&W conversion is ok. im not really a B&W fan, so I dont really have much advice there.
the pose is excellent. I didnt really see her "scratching" her head as much I saw "running her fingers through her hair", but I can see how either one would be visually applicable.
honestly, we could sit here and debate the backgrounds "distraction" level all day, but the real bit that kills this shot is the OOF "side frames".
everything else, to me anyway, is semantics.