I noticed after sex there was tissue/flesh chunck that came out, I had never had that happen or seen it before, it wasn't bloody, and it wasn't a yeast infection what could it be?

Read this, see what happens your next period, and the next time you have sex. See a GYN. (Maybe even bring in the tissue or take a picture)
Not a big hurry unless you are in pain.
Gyno Gab: Passing Your Uterine Lining, Menstrual Period Norms

How long after sex did this happen? Most likely it is congealed semen and nothing to worry about.