Hi there! Well done on deciding to give B/feeding a try.
I breastfed my first little man for 6 months and used a pump quite a bit so that daddy could help out with night feeds / or give me some time off every so often!!
Breast pump doesn't hurt - the suction feeling at the start when it begins to get going feels odd but not painful at all.
TBH sometimes baby was a bit painful if he wasn't in the right position / latched on correctly but again that's easily remedied. The first couple of weeks can be a bit trying / painful as you and baby are gettng used to feeding (so are your nipples!), having your milk come in but once you're careful to ensure he/she latches on correctly and try to feed as often as possible the rest works itself out - and knowing what you're doing for your child is worth a bit of discomfort for a few weeks out of your life while things get going - it DOES get easier and better and before you know it you'll almost forget baby is attached when you're feeding!
Sometimes problems can occur - mastitis is the most common one, but you'll know if something is wrong very quickly and docs / midwifes are quick to help - most important to remember is keep feeding / expressing - it helps to rid the body of infection quicker. I remember having quite sore nipples for a while (after all they're not used to being in someones mouth for hours a day!!) - again, act on the problem sooner rather than later, nipple shields while feeding were a godsend - it just allowed the nipples to heal quicker while not interfering with baby's feeding. Don't mean to put you off , just being honest and you might be one of the lucky ones who never has any issues
But if they do happen, it's not the end of the world, can be painful yes, but can also be sorted .
Not everyone is lucky enough to be able to feed their child this way so I certainly don't take it for granted. Am hoping to be able to b/feed baby No#2 as well - going to give it a good shot and keep my fingers crossed it works out as well for me this time as it did the first time.
Good luck!
bought a breastpump today(not producing milk yet) but tried it to see how it feels.. and im suprised it just tickled! 
