I tend to go through phases. I will either have total writer's block and it will continue for a while (usually if I am stressed or busy at work) or I will have idea after idea. It just comes naturally, I don't know how.
When something comes to you, write it down! It doesn't matter where you are. Then when you have some quiet time, write your article. With Hubpages, you can write hubs that answer questions or use the weekly inspiration topic. If you have a few ideas, write a hub on each! Just don't lay the pressure on yourself.