Sounds to me like you have worn down the enamel on these front teeth and now you're into the second layer of tooth structure known as dentin. Dentin has big pores in it that if exposed to air and water can tingle like pins and needles. My suggestion would be to go to a dentist and see if they need to seal the edges of these teeth with composite bonding. I don't think anything over the counter will help you at this point if he sensitive toothpaste is not working- that's only for mild wear. I think your wear is more severe and needs dental attention. You can get decay in these teeth if there's no enamel so don't put it off.
Hope this helps.