Thank you for the query.
Heavy salivation is usually caused by vagus nerve stimulation
due to some stomach issue. You could feel it as a nausea. Other symptoms also indicate some stomach or esophageal issues. It can be peptic ulcer
, stomach inflammation
, Helicobacter Pylori infection
, esophagus inflammation
. In some cases such symptoms can also indicate stomach or esophageal cancer. That is why it is very important to do not ignore them.
I suggest you to visit your doctor and have abdominal ultrasound, blood work, ECG and gastroscopy done.
In a meanwhile please avoid fatty foods, spicy foods, fried foods, coffee, sweats, soft drinks. DO not eat before sleeping and try to place your head little bit higher when sleeping.
Hope this will help.