H.P.
That sounds exactly like the reflux my son had and the ped always told me he was fine because he was fine during the day. Get a pediatric GI to evaluate him.
He couldn't sleep more than 2 hours without waking and shrieking. They told me he was fine for a year, and then treated him and he improved drastically.
Don't let the docs tell them nothing's wrong when something is.
H.