My friends daughter is getting married and she indicates it's formal.

Well, I am a woman who NEVER, EVER wears dresses or frilly clothes.
I also do not EVER wear heels. I thought of a tux but don't want to
Make anyone uncomfortable. Any suggestions as to what I can
Wear. I'm short and kind of chunky! Also, is black okay to wear.

All suggestions welcome short of staying home.

There are dressy pant suits I see women wearing in formal situations all the time. Unless you are part of the Wedding party a Tux is overdressing even for the guys.

I didn't even wear a tux to my own Church wedding in Europe. I wore a regular suit.

I own a few tux and wear them to many formal occasions.
I would ask the mother of the bride to be polite. To some formal is just that formal.

My niece was just married a few weeks ago. My mother in law decided that she wanted to wear pants, so she found a flowy, black pair. She wore a sparkly blouse with purples, grays, and black. But, the best part was her sequined tennis shoes. She looked adorable and honestly, she was more comfortable than anyone in high heels!

The only real obstical you need to ster clear of and asking your friend will help with it is to try not to wear the same colors as the wedding party. Other then that you have many choices to dress up and still feel comfortable.