Excess saliva + soft tissue aches in top back of mouth + sore throat & heartburn-like symptoms. occasional constipation. worse in morning. any ideas?

Gastric Reflux: It is possible that you have gastric reflux. If the acid from the stomach comes up to the throat while you sleep it may cause the throat and mouth symptoms you describe. You should discuss this with you doctor for possible treatment. In the meantime you can try eating no later than 2 hours before bedtime and sleeping in a semi-sitting position. Over the counter medications may help as well.