i have this problem. my bub is 10 weeks and im still b/f tho i have to top her up with formula due to low milk supply.
my nipple burn for about an hour after a feed and if i get too cold - every time i shower. its called nipple vasospasm i have found breast warmers to help alot. the pain and frequency of spasms are lessening and bub gets older and my nipples grow less sensitive. it was very hard in the first few weeks with cracked and blleding nipples, i had to grit my teeth to aply cream.
check out this website
http://www.kellymom.com/bf/concerns/...blanching.html