Trouble during feeding time.

Hi mummies, my baby is 1 month 14 days now. Nowadays he kept crying halfway through feeding time. We thought it might be because of gas so halfway through feeding time we always try to burp him. Sometimes he’ll burp, sometimes he won’t. But even when he burped already, he’ll still cry. So I will have to swaddle him and then he’ll finish his milk. Swaddling does help. But I wonder why he keeps crying now? Any of you mummies experience this?