everytime after finishing her milk, she would cry as though telling me that she not enough. but few seconds later when I carry her to burp, she ok n keep quiet. why is this so? this happens since about 3 months old till now coming to 5 months...

Is your baby bottle fed? If your baby is crying a lot after every feeding and stops as soon as you burp her, it could simply be a buildup of air swallowed while eating. Bottle-fed babies in particular are prone to swallowing a lot of air during a feeding, which could trap gas in their stomachs and be uncomfortable and painful. This could explain the crying. This article has more suggestions as to why baby is crying after feeding: http://www.healthline.com/health/parenting/baby-cries-after-every-feeding