Tooth has weird taste coming from it.. (hurt, dentist, abscess)

[sunshinelove0000]

I've had this problem tooth for a while. It's quite sensitive and has horrible recession. I am not a candidate for gum grafting (genetic condition/extensive dental issues.. Long story). I had a cavity in the tooth as a teen and it was filled. Since then it's hurt me off and on and yet each time I see a dentist they tell me it looks fine and x-ray does not show anything. Well now the tooth has this funky taste/flavor coming from it. What could it be? I plan on seeing my dentist tomorrow but would like to have an idea as to what it could be? Anyone else dealt with this?

[AnonChick]

It sounds like there's something rotting in there. Either food got stuck and the food's rotting, or there's an abscess, or the tooth itself is rotting.