Breastfeeding tips

Good morning (:

I gave birth to my son 2 days ago, and am really wanting to successfully breastfeed. My issue right now, is my nipples are flat and so I have to use a nipple shield that is used during nursing. He does well with it, but he isn't getting enough or my breast in his mouth so at times it hurts. Do you ladies have any tips or suggestions to help him latch?