Girls, hello. The baby is 3 weeks old, trying to poop but can't. Altho…

Girls, hello. The baby is 3 weeks old, trying to poop but can't. Although she poops regularly every 2-3 times a day. But she's constipated. How can I help her? I massage her tummy and turn her over. Today she didn't sleep all night, maybe it was because of her distress. She slept for half an hour and woke up restless. She coughs.