True writer's block is extremely rare and it is a psychological disorder akin to OCD and phobias. Outside of that medical realm, what people call writer's block is simply fear, laziness, a lack of motivation, a lack of focus, or a plotting black hole the writer can't find a way out of. I've never had writer's block but I have experienced all of the above. And I've worked through them.
I try to equate it to my "real" job as an ER nurse. There are times on the job when I suffer from all of the above (except perhaps the plotting black hole although there are other stumpers that perhaps equate) and there I don't have the option of not doing my job. I have to find a way to work through it, find the answers, get it done. I do the same thing with my writing. When I supported myself solely with my writing I HAD to work through those things. Though I have more flexibility now and do occasionally indulge in a bit of "I don't feel like doing it so I'm not going to," for the most part I just keep on plugging.
Beth