Well, this dude named Erich Fromm talks a little bit about it...
No, but seriously, it's a big deal among certain critical theorists like himself and Martin Heidegger who argue that boredom is a common pathological response to highly industrialized societies. Their criticisms draw from the traditional Marxist school of thought, arguing that these types of societies force people to engage in alienated labor, pulling them away from things that naturally belong together as part of the systematic oppressive process of capitalism. As dogmatic capitalism begins to erase individual identity, boredom becomes a systemic problem. Fromm specifically argues that the never-ending search for novel thrills that characterizes consumerism in industrial capitalist societies is not seeking a solution to boredom, but rather a distraction from the problem of boredom, driving it further into our subconscious minds. And drawing it one step further, Fromm cites boredom as being the driving force behind "aggression and destructiveness today" in his paper, the Theory of Aggression.
Heidegger takes issue with the mechanization of capitalism and how it contributes to boredom. He gives the example of an automobile assembly line, which requires continual physical engagement on the part of the operator, but no real conscious thought. One looks "busy", but really is just perpetually waiting, waiting for the tedium of the job to be over, waiting for someone else to finish a task, etc.
For more on this line of thought, I strongly suggest reading Herbert Marcuse's One-Dimensional Man. It's a great introduction to the Frankfurt School and their thoughts on the culture industry and capitalism while remaining somewhat uncharacteristically lucid. It introduces the idea of "consumerism" as a form of social control, which is truly revolutionary.
Taking a slightly different angle, it's also a notable concept in existentialist literature. Heidegger himself picks up the topic of boredom a second time in his writings on "nothingness" and the meaning[lessness] of existence. To him, boredom reveals a lot about Dasein. In Being and Time, his most famous work, he writes:
Even and precisely then when we are not actually busy with things or ourselves this “as a whole” overcomes us — for example in genuine boredom. Boredom is still distant when it is only this book or that play, that business or this idleness, that drags on. It irrupts when “one is bored.” Profound boredom, drifting here and there in the abysses of our existence like a muffling fog, removes all things and men and oneself along with it into a remarkable indifference. This boredom reveals beings as a whole.
That is, this boredom works to create a pervasive state of anxiety in which Dasein begins to truly reveal itself. Heidegger and the question of psychology is a great introduction to this line of thought that doesn't require actually reading Heidegger's own characteristically dense (perhaps impossible?) prose.
Arthur Schopenhauer (notable, among other reasons, for his profound influence on Nietzsche) also takes up the topic of boredom, arguing that it actually proves the vanity of human existence. He reasons that if life was truly possessive of positive value and real content, then there should be no such thing altogether as boredom. He asks, shouldn't mere existence be enough to both fulfill and satisfy us? The entire book containing this discussion (Essays and aphorisms) is actually available online through Google Books. You might consider reading through it sometime when you're, erm, bored.
And if you have access to scholarly periodicals through a site like SpringerLink, you might try and ferret out a copy of Patrick Bigelow's The Ontology of Boredom, which seems like it might be a direct answer to your primary curiosities.