Painful boob breastfeeding

I gave birth on Tuesday and was helped with breastfeeding and was all good since yesterday but then my left boob is really tender and sore and my nipples are also sore when baby is feeding the nursing nurse at the hospital said he was latching well his jaw is moving and his bottom lip is rolled over but my partner's mum said the areola should be in his mouth too but it isnt?? Any advice please thankyou!

Update:

Thankyou so much to everyone who commented I'll take all the advice I can get! ❤️