Anyone else with Altered Taste All Day Long?

For the past several months I have had a problem with a terrible taste all day. I can taste food but as soon as I stop eating it goes back to either a sour or very unpleasant taste or an overwhelming salty taste. The dentist sees no issues, the medications and other products to increase saliva have done nothing, the GERD medication does nothing to help either so now I am on Gabapentin in case it's more of a neurological issue. This has helped reduce the amount of days when I have an overwhelming salty taste but has done nothing to reduce the constant sour and more tolerable salty tastes that I continue to experience all day long. Gum helps mask the taste but the only thing that really helps it is wearing my old orthodontic retainer. I have no idea why this helps but it immediately reduces the miserable taste, Of course this does not resolve the underlying issue. Is there anyone else experiencing this and have you found an answer????