Hey Yazzy! Great to hear she's doing so well weight wise and feeding. I would double check she doesn't have a tongue tie, it can cause real pain (I was in agony) and it's very very easy to sort if she does. I had no idea how common it was...
This shows you what to look for, https://www.tonguetie.co.uk/ and have a look yourself as 4 midwives missed Sammuels TT!!
Other than that it may just be her feeding a lot. If it continues or gets worse, definitely get some help, don't just suffer. La Leche League are fantastic and can offer support over the phone or probably have meetings in your area too...
PM me on facebook if you want any more info - I don't come on here much but will try to more... xx