What medication have you been prescribed as it could be a side effect.
You could try ALOE VERA DIGESTIVE AID JUICE. I have AR/GERD myself and found it helpful also GAVISCON is good.
It would also help to look up Diet for AR/GERD and I found cutting down on sugar helpful.
The Metalic taste can also be caused by the AR. Did your Dr prescribe PPIs as that is the normal medication. Solofelix.