There's this tickling feeling in the back of my throat and i constantly cough! how to cure this?

Antihistamines: The most common reason for having a throat tickle is allergy. You may or may not have runny/itchy eyes & nose with sneezing; but it is worth a try. Daily, non-sedating claritin, (loratadine) zyrtec, or Allegra should do the trick. This may be a seasonal thing, or may be year round. If it is more of a constant thing, then switch your daily antihistamine every 2-3 months to maintain the effect.