DS had a very minor posterior tongue tie and it wasn't diagnosed at the hospital. Got a lactation consultant in when he was about 5 days old and I was FFing, pumping milk, crying with pain at every feed, etc, and she showed me how to feed lying down so the sore part of my nipples could heal and helped me get an appointment to get his tongue tie divided.
If the TT had been diagnosed and clipped while we were all in the hospital (for 2 days!) it would have meant my first week would have been SO much easier. I wouldn't have blamed any woman for giving up in my shoes. If we hadn't had the seventy quid it cost to get a lactation consultant to come over, I think it would have been the end of breastfeeding for us, and that simply shouldn't be the case.
That said, even if DS hadn't had a tongue tie I think I would have experienced some pain in the first few weeks because I had very flat nipples. Not inverted, but very flat. After 18 months of feeding they're not (!) but they used to be, and I imagine DS had to do some work stretching the ligaments. God it hurt. Separate to the Tongue Tie, that aspect hurt.
A midwife had seen my flat nipples and suggested I try breast shells before DS was born to help stretch those ligaments, but I hadn't clocked that the stretching would be such an ouchy experience.
I live in the USA so I'm sure my experience is a bit different, but the BEST thing anyone said to me in the whole dramatic first week of DS's life was "Every breastfeed you do is wonderful, and any time you've had enough is fine too. Just take it one feed at a time."
She was the hospital lactation consultant, (and while I wish she'd diagnosed DS's tongue tie) I will always love her for saying that. It took the pressure off!