Was there a relationship between Pink Floyd and Rolling Stones?
Roger Waters says 'Will you sell your story to rolling stone' in one of his The Final Cut songs. And also, it was either David Gilmour or Rick Wright, one of them said 'black and blue' in Us and Them from DSoTM. Black and Blue is a song by The Rolling Stones.

Rolling Stone is the name of a music magazine. So that covers your first example, as he clearly wasn't talking about the band. As to your second example, David was the lead vocalist on Us and Them, but that line or rather that choice of words, has absolutely nothing to do with The Rolling Stones. Black and blue are opposites -- black is the absence of color, blue is very much a color. Black is dark, while blue can be both dark and light.

You need to read between the lines in that particular song to understand what Roger was talking about and you'd clearly see none of it has anything to do with Mick Jagger & Co.

It was Roger who came up with the lyrics of that song, by the way. :P Rick wrote the song, Roger wrote the lyrics, and Dave sung it.
Anyway, these clues are a bit... vague. Artists refer to each other constantly (like Bruce Springsteen's reference to Roy Orbisson, or Roger Waters' reference to Webber), and usually it means little more than simply whatever the context requires it to mean.

I've always found "black and blue" to be a bit of a peculiar line in that song, though. Most of it is opposites, or words that are often used metaphorically for opposite things (us & them, up & down, etc). Black and blue aren't quite opposite, and Roger may or may not have had a reason to do this.

Black and blue are definitely not opposite, they're very close. Black is very rich in colours, black is all the colours put together, blue is also a rich colour. As a matter of fact, on the spectrum of light, blue is the darkest colour, you would usually find a gradient of blue, to the point where the blue spectrum becomes black.

Just because Black and Blue is the name of a Stones song doesn't mean if the words appear in some other song, the lyricist was referring to that particular song or band. Especially since to do so in this instance would make absolutely no sense whatsoever.

I agree. I was not aware that Rolling Stone was a musical magazine.

You're mixing up white and black. :) Black is the absence of colour, white is the combination of all.
Not that this changes the point... I think it's a mere coincidence.

It really depends on whether you mean light colours or materialistic colours. The combination of all colours on paper, as in with materialistic colours is black. But, yes, since the album of DSoTM shows a light spectrum, meaning we're talking about light colours, you're right.

A coincidence it is. Does anybody know what black and blue stands for?

Black and blue is used denote bruising, but in this instance, that definition does not apply. I think Roger just used the word "blue" after black because it's an easy word to rhyme.

It kind of stands out for me. But, okay =D Thanks.