Last two upward teeth is getting sharp.

The sudden appearance of sharp edges on a tooth is less likely because of traumatic crack of the tooth but more importantly and commonly because of the fracture of unsupported enamel caused by Cavitation. This is more evident by the fact that you also have pain in those teeth. This basically brings us to the conclusion that the teeth are affected by Irreversible pulpitis and will require root canal treatment followed by Crowns so that your symptoms are alleviated and the teeth become strong enough for sustaining the biting forces on a daily basis. Please search for a dentist in your vicinity using Practo and try to get the treatment done as soon as possible before the symptoms aggravate further. Regards.