my kitten is sick and she can't sit on her butt and poop coming out of her but

Hey my name is Patricia and my kitten is real sick she can't sit on her butt cause it hurts her and its puffed out and poop is running down from her butt what should I do

A vet visit is in order.
How long has she had diarrhea?
How old is she?

Kittens get dehydrated VERY quickly and can go down hill quickly as well.
Keep her hydrated. Give her canned food, add a tablespoon or two of water.

She needs a vet visit as soon as they open where ever you live.

How long has this been going on?

How old is the kitten?

Is there diarrhea?

What is her energy like?

Is she eating?

In addition to what others mentioned:  if diarrhea is present, Pedialyte may help restore her electrolyte levels.

Put in enough water that the food looks soupy. Get her to the vet as soon as possible. From your description of her hind end, it sounds like this has been happening for awhile. The sooner she gets to the vet, the better. You don't want her to crash from dehydration and exhaustion.