I still remember when this happened with Lil K when he was around 1 month old. He was crying for hours and the worst was that it seemed like everything we did to soothe him down was wrong. I fed him full, changed his diapers, swaddled him, sang him a lulaby, hug him, we did everything but he still cried excessively to the extent of made me think "Am I a bad mother? That I cannot comfort my own child?".
If you're having the same thing like I had with Lil K, well don't worry, moms! It's really none of your fault, nor your baby's. Big chance is that you're baby is having a colic.