My 4 and half month old had an excellent latch from the start. He was a home birth and was on the breast shortly after birth.
Recently he has been latching on then, while sucking pulls away from my body, still sucking. I'm starting to get a little sore. I've tried holding him in close to me, but he pushes his head back against my hand. No matter how many times I take him off the breast and try to restart he does the same thing. He seems to have his own idea of how to nurse. I've also tried different holds (i.e. Football) to ease some of the pain but he gets frustrated.
He is teething as well.
I have a 10 year old that I nursed for 20 months but that was so long ago I can't remember if he did this or not.