We can imagine such a situation that 2 months ago I got some special project which I have to be working on. Now I've been working on it. And I can say:
1) I am working on it
Pointing at my action like at some temporal period of time. I am not working right now, because it's night, but at this period of time, yes, I am working.
2) I have been working
Pointing that I have some deal, I got it in the past and I have been wroking on it since then.
The problem is it seems to be completely Interchangeable and I see no difference between them. What to do?