@SRS1311 our LO was like that our first night home (at 5 days) having taken 3 hour naps happily in his crib all day downstairs. He was falling asleep after feeding then immediately waking in his cot and crying as soon as put him down. We found a hot water bottle on the sheets before bed worked wonders - the change in temperature from my warm body to the cold sheets seemed to be waking him. He is now nearly 5 weeks and apart from the odd bad night he sleeps between 4 and 7 hours when we put him down, no hot water bottle required! We have also kept a very strict and repetitive bedtime routine of going up same time every night, dark room, lullabies, bath, change, feed, cot. Not quite sure if he knows its bedtime or just a fluke but it seems to be working! He now stays awake for much of the morning and evening and sleeps most of the afternoon and night.
We've had one or two rough nights where he wakes on lying down due to his tummy so it could also be that. We could tell it was wind as his tummy felt rock solid and he just looked so uncomfortable. I found the wind tended to build up over the day so whilst he was ok to lie down during day after a lot of burping, sometimes by nightimr the wind seemed to have accumulated. This only happened when my milk came in though. We have started giving him infacol and I burp him A LOT including mid feed, even though he is breastfed, and he is so much better.
Oh also , on his second night in hospital he would not sleep at all due to mucus so it could be that? Apparently newborns have a lot of mucus in their system and can get congested, this is also worse at night and when they are lying flat. Theo screamed thr house down and I had to ask a midwife to take him for a walk as was at my wits wits end. If its that it would be just temporary but you would be able to hear bunged up sounds? I'm not sure if its advised to use on very new babies but the few times theo has woken at night recently due to congestion we have used saline spray and nasal aspirator to try and decongestant him a bit - seems to be helping.
Hope you find a solution, I really feel for you. Obviously every baby is different but in my, extremely limited , experience, the LO will be crying for a reason however difficult it is to pinpoint - it's a bit trial and error but find the reason and you can hopefully find a solution 