Hi! The right side near my belly button is a little bigger than my left. It is not noticeable to other people since they can t see it from the top like i could. but i could definitely see the difference. Also a little below my rib cage, the left side is bigger than the right. I ve searched on the internet the possible causes for this but everything seems to lead to pregnancy . I can t be. Since I have been having my periods (in fact, I just had it last week), and I had an ultrasound yesterday, which also said that I was not. Pregnancy test also said negative. Sometimes I also have pains that come and go in those areas which i said were bigger. Also, sometimes my back hurts.