Sleep deprived!!

My LO is 3 weeks old and does not like to lay flat. He sleeps hours in his swing during the day but won't sleep in his pack n play or bassinet. I don't want to leave him in his swing all night to sleep. I bought the Snuggle Nest co sleeper that goes in my bed and used the incline insert to see if that will help him and it does a little but he always wakes up grunting and pulling up his legs close to him like he's uncomfortable. Idk what to do?!