Inconsolable crying

Hailey • Mother of 3 amazing children! 👦 03/04/10 👧 04/29/12 👶 01/07/16 ❤️️
Last few days my son (4 months) has been inconsolably crying.
He will not peacefully nurse, always cries sucks cries sucks over and over until he gets tired and feeds but then falls asleep shortly after, but then after about 20 minutes of sleeping he will just start screaming in his sleep and nothing I do makes it better, the inconsolable crying happens all through the night as well.
It's not a straining cry either so I don't think it's gas, he has been teething the last few weeks but I've never experienced a baby waking up crying from teething pain. 
Can someone help?