Girls, the baby is one month and a week old, he used to sleep well at…

Girls, the baby is one month and a week old, he used to sleep well at night. Now something strange has started happening... He's pulling his arms and legs very hard. It also happens during the day, he sleeps well only outdoors. He doesn't cry, everything seems fine, but he's very actively jerking around... What could it be? A growth spurt? To see a neurologist only on 21st, he never did before.