Hello C_F,
With acid reflux at night, I would wake up coughing and a sore/burning throat too.
Using 2 pillows for a few weeks helped me a lot. Maybe it does keep the acid down and prevent heartburn. You might be facing this problem only at night - maybe because you are lying down only then? Do u nap during the day, and do you face this problem that time too?
Also try eating a cookie or a tiny bit of bland food every 2-4 hours and see if it helps even a little bit.
When my tummy is empty I get the burning/pain/etc (in my chest/tummy - centre and left side) . Then I nibble on food every few hours and the pain vanishes.
Oh i sleep on my left side too, when in discomfort, not sure why, but I do. :-)
Hope this helps, maybe a doctor may also have other things to check for? Do take care.
:-)