When too much air becomes trapped in the stomach, it leads to discomfort, and that can cause any baby to cry. This is where burping comes in. ... Sometimes, babies take in a lot of air while they're nursing or bottle feeding because they're not in an ideal position.
My LO also spat up after burping at that age, but it just stopped by itself after about 6 mths. I also stopped actively burping my LO and just let her burp on her own. She preferred that too. Haha
Possibly with all the wind rushing up when burped it gets alittle uncomfortable so LO cries
Gripe water works well for my LO when he was around 5 months .