Tooth pain ?

Why do my teeth (molars) hurt only when I chew gum ?

Everything else I eat they don't hurt but when I chew Minty gum it hurts afterwards a little only on one side where I do have fillings I have the metal color fillings I got these fillings about 6 years ago but I just had a dentist appointment last month and the dentist said my fillings looked fine and I had starting cavities but no fillings needed and I floss about 3 times a day