Hair growing/healthy hair tips?

I'm in need of hair growing tips! I have shoulder length hair and nothing's helping it grow. I haven't used heat in my hair in about a year. I died it in January, and I decided that's going to be the last time in a while. My hair used to grow like crazy when I was a teenager. But I also used a lot of heat,products and hair dye. So I don't know why it's stopping now. I heard to trim it once every month, and when I do it just seems like it's getting shorter and shorter. My goal is to grow it out past my boobs. But with it not growing I just want to cut it all off! It's driving me crazy. I've taken itworks hair skin and nails, which it did work but I honestly didn't like spending so much every month and I hated having to take 2 every day because I forgot a lot. I do deeep treatments every now and then. I wash my hair everyday (it gets super greasy). And I sometimes brush it. It's mostly in a bun. And that's it. I use shampoos that help with dry and damaged hair but it's still gross looking. I need help.😩😩😩😩😩