Baby grunting all night.. is this normal?

Our little one is 9 weeks old and has pretty much grunted like this all night every night since he was born. The only time he is really not grunting is maybe the first time he goes down in the night for 2/3 hours. After than he will grunt continuously in his sleep and only stop if I Put him on his front on my chest.

Has anyone had any experience with this and why did you do? I’m finding it increasingly hard to sleep but more worried he’s in discomfort.

He’s exclusively breastfed, no underlying health conditions except for a heart murmur (diagnosed as innocent) and I am currently dairy free (week 2) as he’d had small streaks of blood in his poo on a few occasions and they suspect milk allergy.