Always painful when latching on

Help! First time mum here. It’s been 2 weeks of trying to latch on for breastfeeding but my nipples are always painful when my baby sucks. I have tried different breastfeeding positions, holding my breasts in a C/U shape, aiming my nipple at the roof of baby’s mouth. My nipples feel sore and tend to look flatten when I unlatch. Anyone has any tips to share for a better latch? Should I try using a nipple shield? #advicepls #firstbaby #firsttimemom