As you have been diagnosed with GERD
already then yes the symptoms you have mentioned maybe because of GERD.
GERD is a disorder where there is regurgitation or reflux of food material from the stomach to the esophagus
due to a weak esophageal sphincter (the junction of stomach and food pipe which is normally tightly closed to prevent the food from coming back into the food pipe).
When there is reflux of food along with it acid also comes up into the food pipe and causes damage to the food pipe. sometimes this may come upto the throat and lead to the symptoms you mentioned(pain, cough
, white tongue).
So i would advise continue taking medicines for your GERD problem properly. Also take lighter meals and avoid sleeping immediately after you eat. while sleeping keep a slightly propped up position with a pillow under your back.