Sleeping on your side isn’t a problem babe, Its just your skin stretching due to them fluffing, I’ve slept on my side to & have had no issues, I wouldn’t worry, everyone’s body’s heal and react differently, it’s definitely not because of the position you sleep in, sleeping on your side is recommended for the first week & that is due more to comfort as long as you wear your bra for 6 weeks your boobs will stay in place x