Baby don't like sleeping on their backs!!!

Idk why the hospitals/doctors tell you to not let baby their stomachs. You ever notice how they'll sleep on your chest but as soon as you put them down they wake up?? Try putting them on their stomachs!! I couldn't figure out why my daughter wouldn't sleep more than 5 mins, I put her on her stomach she sleeps 3-4 sometimes 5 hours! Just think if you were a new baby being on your back stretched out doesn't feel good! They feel cuddled up and snug on their bellies!