Following are the common causes of abnormal taste in mouth:
1) Post nasal drip
2) Sinus infections
3) Peridontal disease:dental infections/diseases
4) Gastroesophageal reflux disease
5) Alcohol and caffeine drinks which makes one dehydrated and thus this sensation
6) If you smoke this is a possibility
7) Medications; the side effects can appear anytime
Drinking plenty of fluids and avoiding the caffeine and alcohol drinks is the first step of the management.
Examination by an ENT specialist and a dental surgeon is the second step to look for the cause. Inadequate saliva secretion, which can happen due to medications or because of lack of adequate fluids can also be responsible.
But it is never anything very serious (although annoying), so you should not be worried.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
Thanks for using Just Answer.