My 3 week old will only sleep while being held. Not a chance of getting him into the Moses basket and even co-sleeping he wakes up 10 mins or so after being put down. He sleeps for hours in our arms even if he's lying flat so I'm not suspecting reflux, I think it is just a case of getting used to being in the outside world.
I know DC1 went through the same phase but can't remember how long it lasted. If your DC were similar, how long did this phase go on for? We are horribly sleep deprived from taking shifts through the night and want some hope that the end is in sight!