Babies cry a lot so how do you know what the difference is between an I am tired cry or an I am in pain cry or an I am scared of you cry; that really depends on getting to know your baby. As you get to know your baby you will be able to identify which cry goes where. Generally the I am tired cry is a more flat drawn out cry and then the I am in pain cry would be a very sudden onset high-pitched cry as would be an I am startled cry. And usually a facial expression with the cry will help you figure out what's going on. If a baby is crying for a long periods of time and no matter what you are doing they are inconsolable that's the cry you need to check out. Usually if a baby cries and you offer them a pinky, a pacifier or a bottle, cuddle, holding them or rocking them if that doesn't help something else is going on and you need to figure out what's going on. If your baby seems to be happy and all of a sudden has jags of intense crying out of the blue that's some thing you want to look at. That could be a sign of reflux and you want to figure out when your baby is crying and how they are crying and the best way to do that is really observation. Matching the facial expression to the cry and realising what works for each particular cry. Again in the beginning I am in pain is the high-pitched cry and I am tired cry is a kind of lower and longer cry. But the person who is going to know your baby's cry best is you after you get to know them and spend some time with them. Remember the babies can't talk so the only way they can communicate with you is for them to cry.