I exclusively pump and i started 2 days after my baby was born because she just wouldn't latch and I wanted to give her only breast milk. I recommend starting as soon as possible to establish a good milk supply! I never had problems with a painful oversupply... 🙃
It's not recommended until six weeks. you can hand express and keep warm washcloths on them. (Save the breastmilk you can either freeze it or save in and use in your babies bath) if you absolutely have to pump then do it when your baby would normally eat but dont over do it because you can cause a very painful oversupply.