You might have an infection of the gums so i would definatly go to the dentist to get it checked out and cleaned. It myt be something a dose of antibiotics may be able to fix!!
Also agree about the floss you would be surprised how much food can hang around in the tiniest of places so get that, or i am loving the sample of the pixters i got its like a mix of a brush and floss its really effective my teeth feeel sooo clean after using it!!
