I have what looks like a brown stain on my molars near my gumline. I don t believe it could be a stain because it s VERY sensitive when it s touched. I haven t been to a dentist in a while, since I was pregnant 6 years ago. But I do brush 3 times and day and floss before bed. I am a smoker and I live on coffee, therefore I bleach my teeth once a month. I thought I ve taken extra care of my teeth, but I m noticed in the last couple of months that only the back ones hurt. When I have something cold, or hot, or touch the spot the pain is agonizing. I know I should see a dentist, but I do not have insurance.