Can somebody tell me if they know any death metal bands/songs that discuss social alienation in their lyrics? If you know any songs, you should post the lyrics.

Hmmmm, I'll take a stab at it. I think thrash metal is more suited for this subject. I won't post the lyrics due to the content, but try some of these songs, with links to the lyrics:

Are You Dead Yet? — Children of Bodom
About how he hates himself.

http://www.songmeanings.net/songs/view/3530822107858560767/

Tie My Rope — Bodom
About the suckage of life lol

http://www.songmeanings.net/songs/view/3530822107858705960/

Architecture of a Genocidal Nature — Dimmu Borgir
What could be more alienating socially than genocide? The whole song could be construed as a collapse of the world as we know it due to the societies that segregate themselves from one another; society or religion, as you decide.

http://www.songmeanings.net/songs/view/3530822107858537137/

Suburban Me — In Flames
About someone feeling alienated because he has bigger dreams than the world around him.

http://www.songmeanings.net/songs/view/19396/

Withering Away – Kalmah
Difficult to decipher, but he *does* say "a matter of social needs" lol. I'd say this is alienation to the point of suicide, hence the title.

http://www.songmeanings.net/songs/view/89170/

Cast Down the Heretic — Nile
LOL the name says it all. This is what happens when you incorporate change into a culture.

http://www.songmeanings.net/songs/view/3530822107858578281/

Nothing — Norther
I think a lot of songs by Norther would make some good examples, lot of feelings of being alone, outcast, in time of war too, even.

http://www.songmeanings.net/songs/view/3530822107858513237/

Dirge for November — Opeth
Suicide. This is suicide. I suppose you could say social alienation was the harbinger haha.

http://www.songmeanings.net/songs/view/44202/

Burden — Opeth
The deceit of society alienates, becomes the burden to, this person.

http://www.songmeanings.net/songs/view/3530822107858718308/

Sleeping Stars — Wintersun
Removing one's self from society purposely. Feel the cold, see the distant fires.

http://www.songmeanings.net/songs/view/3530822107858522920/