My 3 week old constantly makes this super-loud throat clearing noise constantly after eating, for hours. And she makes it all night She also makes this hacking sound, like a person trying to hock a loogie. She sounds exactly like my grandad did when he was trying to get junk out of this throat.

Is this a sign of post nasal drip? Or reflux?

She definitely has it more often after eating or when we put her flat on her back, but even in the Rock n Play, she will do it occasionally. When she's in her crib, it's nearly constant....even though we try to keep her upright (on our shoulder) for 30-45 min after eating.

We've tried the humidifier for the past few nights, but that hasn't made a difference. We tried putting books under one side of the bed so we can get a bit of an incline, but it just made her slide down a bit and didn't really stop the hacking/throat clearing. Holding her on our shoulder is the only thing that makes her stop, but I can't very well do that 24/7.

She doesn't sleep when she's doing this, so it's disrupting our sleep, too! Even if she falls completely asleep on us, the second we put her down on a flat surface, she starts the hacking, wakes herself up, and then we have to start all over. I've tried waiting it out (just to see if she's hacking in her sleep and will continue sleeping), but 9 times out of 9, she will continue making the noise until it escalates into a full cry and she's wide awake.

Did this happen to anyone else? What was the cause?