Why Does My Mouth Keep Producing So Much Saliva?

I am a 25 year old white male in good health and good physical condition, no allergies that I know of. Over the past 2 weeks, for some reason, my mouth has been producing a lot of saliva non-stop and it's forcing me to keep swallowing like every couple of minutes. This constant swallowing is upsetting my stomach, I am getting heart burn and also my esphogus and throat feel like there is almost something stuck in there (like right in the center of my chest it feels like I have something stuck in my throat sort of). In the morning it's usually the worst with producing a lot of saliva, and throughout the day the saliva production continues but slows a little. At night when I go to bed I have no issues with saliva and I sleep well and have no heartburn, etc. This just started happening and i'm wondering if it could be something caused by maybe allergies I am starting to get or maybe stress and anxiety I may have, etc.. Is there any medication I can take to stop this or could it be something more serious. The more I 'think' about my mouth producing saliva the more it happens. I notice that if my mind is concentrating on totally something else I don't appear to have this problem.

Any help would be greatly appreciated, thanks!