I always figure if you've gone through labour, a piercing is a complete walk in the park!!!
I have a pretty high pain threshold so piercings honestly don't bother me for more than the three seconds of stinging it takes to get the needle through skin, but I really don't think navel piercings are that bad. My navel was my first 'real' body piercing (ears don't count lol), my parents took me to get it done for my 13th birthday and I didn't use creams, patches or any form of anaesthetic... It stung for a few seconds but yeah after that it was all done, the healing process was worse because of the itching and rubbing against clothing!!

But yeah, just try to think of it that way - you've birthed a child, there is nothing on earth more painful than that, and a piercing might hurt for a couple of seconds but then you have years of a gorgeous little sparkle on your bod!! It's worth the momentary pain