My baby keeps moaning and crying once eves few mins?

he may be constipated, if that is the case try feeding him certain fruits that will help his little tummy work it out. if he isn't old enough for solids look for juices, i hear apple juice is good for loosening things up. also you can try gently maging his stomach in circular motions... hope this helps, i truly know how frustrating it can be with a fussy baby, best of luck to you