My LO keeps fidgeting when carried by me

Not sure why but whenever my LO cry or fuss at night and I try to rock him back to sleep he will keep fidgeting. Like pushing his head backwards, pushing his arms on me etc. I feel like my arms are gonna break 😭 but when my husband carries him he won't fidget at all?? Am I carrying him wrongly or? He is turning 7 months soon though :(