Gas, Reflux?? 1 month Old...

Question for you experienced moms,

My baby about twice a day screams bloody murder. He shrieks so loud it actually hurts your ears. He is normally not like that so we dont know where it's coming from. His face gets all red and hes inconsolable. We notice he has been farting a lot and once he projectile vomited and he instantly stopped crying once it came out. We think its gassy stomach but my cousin said maybe acid reflux. What do you think? What causes this how can I fix it. He honestly seems like hes in pain when he cries . Help