Is it the case that the tension that we experience today is between modernism and postmodernism? 

It seems to be the case to me, but I'm not even sure how to verify this without doing a LOT more work to increase my breadth of philosophy.

The postmodernist in me would say that the search to understand “the tension we experience” is flawed from the outset because there is no single, shared tension with the same content or causes. That being said, I’m not a postmodernist. And to answer your question I would argue a lot of the tension today is ideology using postmodern language games to make discourse impossible.