how to transition to exclusively pumping?

Abbie
5 weeks of ebf and the occasional breastmilk bottle I can't hack it any more. It's so painful still (have inverted nipples and babe has a small tongue tie) although the for the past 2-3 weeks the latch looks fine to me, I'm still in constant pain and discomfort. Iv seen a lactation nurse 3 times and will be going again next week, if after that appt breastfeeding doesn't become easier I'm switching to pumping because I am miserable! 
How do I make that transitions? 
Any tips on storing, thawing and warming??
What's all this about hind and for milk? 
Any advice or knowledge would be great!