My 3 week old screams everytime he passes gas, and no bowel movements since early yesterday…

Try some tummy massages, bicycle exercises (bring his legs to his chest, and put them back down) you can also try a warm wash cloth on his tummy. Another thing you can try is stimulation, you can put a warm cotton ball on his bottom, or even try to take his temperature rectally to stimulate a bowel movement. Hope that helps!

thank you! I'm gonna give that a try @vb95

You're welcome! My son was constipated all the time as a newborn, usually the combination of those things would help him poop! @amarie98