What Causes Metallic Taste In Mouth And Enlarged Neck Glands?

I have a metallic taste in my mouth for the last couple hours. Several neck glands are enlarged which is a periodic condition for me. I have been overly fatigued and stressed for months. I am obese. I have an intermittent dry hacking cough with dry mouth with leukeplakia which is likely due to long term medication consumption. I have sleep apnea, high blood pressure, high cholesterol and dysthymia. The metallic taste in my mouth is something new to me. I have not eaten anything out of my usual diet. So my bottom line question is, why does one get a metallic taste in the mouth?