Hi sir....
There are many possible reasons for sore throat...
**common cold ,flu infection,other viral infections like mumps,chicken pox,infectious mononucleosis
**strept throat and other bacterial infections
**Allergies like pollen,grass..
** Dry air
**smoking,chemicals and other irritants
**Injury like cut in neck
**cancer
**Gastric disturbance like GERD
Next Steps
As you have history of tobacco usage it is better to visit dentist as soon as possible to rule out cause without delay .