Medela Breast Pump help?

well. my son has Jaundice and was at the hospital - while there my chest became engorged and very sore... i realized i was also leaking and that it was that colastrum? well. i tried to breast feed him but I am inverted and with him being in the hospital for so long - he wont latch on - hes totally attached to bottles! :( so i bought this medela breast pump - and it really hurts. is it because my chest is sore that it makes it painful for now? am i using it incorrectly? my nipple goes into the tubing and im not sure if that is correct or not... maybe the flange needs to be larger? i tried it once and now everytime i want to do it again i just get so upset b/cuz i know it will hurt and that makes me not want to do it... any advice? thanks!