Ay, normal lang yan sis, lalo na kung newborn pa lang or konting months pa lang! Marami sa amin na moms, ang babies namin ay may ganitong kulani from lying on their backs, it's just from the position nila while sleeping, hindi dahil sa sakit. Pero kung worried ka talaga or kung tumatagal lang ng matagal, better check with your pedia para maging sure lang, okay? Don't worry, most of the time it goes away on its own na!