What's more cliche' than a writer writing about writer's block?
I'll just say this up front: I don't believe in writer's block. At least not in the way that most people describe it. I'd rather call it apprehension or better yet writer's doubt.
When an artist first starts out creating things they have a simple goal in mind: they want to express something intangible. They have a need to see an idea in their head materialized in reality. This need is often driven by feelings that the artist has about their view of the world. Something that seems off to them, something that needs to be said, something that people aren't paying attention to. Any of those inclinations can plant a seed of a project and, once those seeds are planted, only time and energy are required to bring them to fruition.
Those types of projects are usually the best.
Unfortunately, to live as an artist, you have to consistently produce new work. (The great censorship of capitalism is that we must sell what we create.) However, once you have tapped out the initial expressive ideas you are left with an empty well of interesting concepts and novel ideas. There is nothing demanding your attention, at least if you had sufficiently expressed your distress in the first place.
So you languish.
Nothing seems right. Nothing has the same flavor as what you made before and you search for ways to reinvigorate your work. You question what it was that made your work popular in the first place. You wonder if what you created was a fluke. You wonder if you are actually contributing anything to the world at all, and when that happens you lose the drive to finish what you were working on. You have created your writers block because you have robbed yourself of the very reasons you created your art in the first place.
By forcing expression we are in fact gagging our voice.
So what do you do? Well, for starters, you re-explore the ideas and feelings that led you to create in the first place. No amount of art in the world can sufficiently answer the issues of society, so there's a good chance that the issues you have with it are still out there. And if, by chance of societal evolution, those problems have gone away, then there are certainly new issues to arouse your creativity. Art doesn't answer societies ills, not in the same way that government and religion can, but it does serve to illuminate and illustrate the realities of our existence while providing a beautiful emotional ideal for us to weigh ourselves against. Once you have re-connected with those observations that planted the seeds in the first place, you will find your resources rejuvenated.
You cannot allow doubt to get in the way of what you create. You may make something awful, you may make something wonderful, but by simply creating you are contributing to a vast and evolving puzzle of creation that contributes to the human experience. To art, the value of a blockbuster and that of a single seller are the same: something has been shared, something has been exchanged, and something has been expressed.
Do not worry how the world will receive your work, the remarkable thing is that you gave it in the first place.