Hi my son was born on May 7 2022, now he is a month old. Since two days he is spitting bubble saliva especially while sleeping. And he prefers sleeping on the lap than on bed. If we try to put him on the bed he cries aloud and wakes up. Sometimes makes grunting sound while sleeping. To avoid flat head i used memory foam infant pillow since 4 days. The main thing is why does he spit bubbles. Is it normal?