When I get nipple pain these days it is always linked to ds drooling much more - I figure that it is teething, although he starts drooling about a month before there is anything to see! However, the reason it hurts me is that his drool is much more acidic when he is drooling a lot more - I can see that it is irritating his face as well, as he gets a rash round his mouth. Is hamish drooling more than usual? If it is irritation, then that might well cause a small tear - I second the lanolin.
And all of mine have done the pushing away thing - it hurts a lot! The girls added twisting their heads into the mix as well, just to make sure that I really felt it!