Help! 4 week old will only sleep on me!

I'm having trouble getting my 4 week old to sleep anywhere besides my chest at night. We have tried putting him in his rock n play and we've tried a co sleeper bed at night with no luck... once he falls asleep I try to either put him in the rock n play or co sleeper and he starts grunting right away and eventually wakes up and starts crying. Sometimes I can get him to nap in his rock n play during the day for maybe an hour or so, but thats about the longest he will stay asleep without being held. 😞 He will be going to daycare in 4 weeks and will need to be able to nap in a regular crib while he's there. Any suggestions would be appreciated!! 🙂