The word translated "heel" in the Hebrew is ʿāqēḇ and is defined as " a heel (as protuberant); hence, a track; figuratively, the rear (of an army):—heel, (horse-) hoof, last, lier in wait (by mistake for H6120), (foot-) step."

https://www.blueletterbible.org/lexicon/h6119/kjv/wlc/0-1/

So I think trying to stretch this word to mean the male genitals is exactly that, a stretch. As for the multiplying of sorrow and conception this is referring to "birthing pangs".