Your problem seems to be a general pocket formation in the affected area, specific sensation to sweet is suggestive of that. You may consult our Dental Clinic for the same in Dwarka. The link is given below https://plus.google.com/103975386117536236648

there would be some exposed root or cervical abrasion because of which u have sensitivity ,or u might have attrision  which is causing sensitivity,it can be cured with filling so consult a dentist ,they will solve ur problem,u can use sensitivity tooth paste but that will help u only temporarily, so for permanent solution visit dentist .

Sensitivity can be either because of wrong brushing habit due to which the dentine gets exposed or it may be due to deep cavities present. If it is due to exposed dentine then you can switch to soft bristle toothbrush and along with that use SHY NM toothpaste. It is very effective . Within a week your sensitivity will be gone but if the problem still persist please visit dentist to get restorations done in your cavities. I hope dis helps. Enjoy