When I try to wear my 3B type hair down, it gets really poofy, stiff, and frizzy?

Okay so I have type 3B hair but all my life, well like 5th grade and up I've always continuously, back to back, used to straighten my hair. So my hair is damaged. I straighten my hair every now and then now but I went natural in the middle of 2013. Ever since then I can NEVER get my hair to come out like I want. I tried people's advice on Youtube and everything, and still nothing. It's really frustrating because in the morning it looks okay but during the day it poofs up bad, it gets stiff (doesn't move at all) and gets frizzy. It's frustrating and I need to know what I'm doing wrong. Usually, I pineapple my hair at night or twist it and put a satin cap on then in the morning I let my hair down and put it sections and apply custard and oil to my hair after spritzing it then I go. My hair wet is like just touching my shoulders but straightened, it goes down my back. And my hair usually dries up right under my ears ): Any alternative hairstyles will help too. If I wear my hair in a bun or ponytail I usually put gel on my hair and I don't like putting gel on my hair but nothing else will hold my edge down but gel and I've been using gel all my life but as I learned more about curly hair I learned that I don't want to use it anymore.