Hello Thank you for trusting HCM Dear GERD can cause reflux and cause throat irritation cause morning saliva production. If it is contained bubble means it is respiratory in origin.Mucus is often produced because of inflammation in the sinuses, nose or airways. The most common cause of this every morning is because of an allergic reaction. Many people, even those without classic allergies, can have allergic symptoms. Common allergens include dust mites, pollen and dust. These are very common in bedding and pillows. Therefore a common story is that as you lay down to sleep, the allergens cause inflammation and therefore mucus when you wake up. This then resolves during the day as you are away from the pillow/bedding. There are other causes of inflammation that you may just notice more in the morning. Most common is smoke. Smokers often have excess mucus production. Also polluted air can do this. Infections can cause these symptoms, but it is quite unlikely to have an infection for such a long time. Finally some lung diseases like chronic bronchitis can cause this. It might be worthwhile changing your pillow and airfilter. If your symptoms not improved consult your doctor he will examine and treat you accordingly.