Could someone tell me what the normal behavior for a 1 month old baby is?

My son cried all the time until well after his first birthday. Sometimes they cry when they're bored or over stimulated. The only thing that kept my son from crying was carrying him with me everywhere. My daughter at 1mo was totally different. She was always very content, slept a lot, barely cried even when she was hungry. Every baby is different. Could be his tummy hurts from switching back and forth from formula.