Yes, nipple pain is quite normal. After a while it can become fairly intense, and it gets to a stage where you will really notice whenever something brushes against them. But it is a good pain because it is the harbinger of growth.
As far as the other questions go, well your personal growth and the speed at which it occurs and how far it goes...there is no good answer.
Sorry.
But it depends on so many variables... your weight to height ratio, your age, your genetics, your diet, your program, your health...all of these factors affect your growth and each of us these factors are different. But if you have a good program and stick with it, it is pretty certain that you will, in most cases, see growth.
I think that is the about the only truthful way to answer.
Hugs!