I create my text boxes and then I shade them. They look good in the design phase, but
when I upload my site there is a bunch of vertical over flow. My boxes swell. What am I doing wrong?

Do your boxes (the containers) swell, or is it the text that fills them?

If the text is bigger than before, you may not be using web-safe fonts. Another factor is that browsers differ in their line spacing -- more obvious for large text objects.

If none of that helps, can you post a link to a problem page?

The containers themselves. The text remain's the same size.

Do you have relative sizing turned on for the shading rectangle? It is usually located on the bottom toolbar. If this is not the problem, please post a link to the page showing the problem.