Sometimes when I sit down to paint or draw, I have an image or theme in mind. But usually I don't. Like on this one--I started with the face which led into the body which looked like it was pulling something, hence the little wagon. And when I tried to figure out what she'd be toting behind her, the "My Burden Is Light" came to mind. I think it is a message to me, a reminder that I tend to borrow trouble and stress about things I have no business stressing about.
If you need the reminder too you can pick this up in my shop.