My 4 month old keeps pulling off my breast?

Naree

After a little bit of help and maybe someone has had a similar experience. My son is 4 months and ebf his appetite is fine everything seems to be okay but when it's time to feed he will latch on have some milk and then he starts pulling off and arching his back and whining in discomfort eventually he totally refuses to have anymore. I'm still burping him well and have tried gripe water and infants friend and also panadol. His been like this for 3 weeks maybe now and I just feel like he isn't getting enough to eat because of this. We seen our doctor and all he had to say was as long as he's having wet nappies he's fine 🙄 well he obviously isn't fine if he's in pain! Someone please help us!!