Hi,
In this age of yours most of the time the glands in the throat atrophies with little production of mucus, hence you need to drink plenty of warm water, avoid smoking if any. Please let us know whether you have acidity problems. People having acid reflux disease are more prone for the dryness of throat. Any more doubts you are welcome.
Regards
OHNS2010
To me it sounds like maybe an allergy problem - you may want to try some type of allergy medication - but of course, please check with your doctor or pharmacist before starting any new medication, especially if you are already under a doctor's care for anything.
For non-medicinal help, you can try sucking on some hard candy - or even something like a hall's cough drop. I personally really like the Hall's Fruit Breezers - they help keep my mouth and throat moister - and they're non menthol, which I prefer as I find the menthol in some of the cough drops actually makes me cough more.