Hi, I've been having this trouble for over a year now!
I absolutely love citrus fruits like lemons, oranges, and grapefruit. But last year when I drank some orange juice, after I had a bad head cold, I could taste the flavor of what I thought was just the orange in the back of my throat still up near my nose. I told my wonderful mom and she said it was just nasal drip so I continued to eat and drink those lovely citrus fruits. After about a month I realized it didn't go away still that the taste was still there. I had a Halls Vitamin C drop and after that I realized it wasn't the orange I tasted or the grape fruit or anything it was the Vitamin C itself. I told my dad and he said it might be allergies so I decided to ignore it and eat the fruits anyway. Year later its still there and it's SUPER annoying! What can I do to fix it?