Hi Craig- You should see a good Ear Nose and throat Doctor who specializes in singers. You might possibly have acid reflux hitting the back of your vocal cords causing them to swell and it feels like thick mucous- sometimes a lump in your throat sensation- causing you to try and clear it with clearing your throat. A good Dr. will put numbing medicine in your throat and actually look at your cords. When there is redness and swelling at the back of throat they then know it's reflux. You may never experience any heartburn- I didn't- I was hoarse and clearing my throat alot. There are good medicines that help- nexium, prilosec etc. and diet is very important- avoiding acidic foods like tomatoe sauce , orange juice, and alchohol.
I've been singing alot- it can be managed quite well. Some ENT's don't "get it" so be sure to get someone who treats singers.
Good Luck!