Brief Answer:
Probably suffering from Chronic Laryngitis.

Detailed Answer:
Hi,thank you for posting your query on health care magic.

I have gone through your query and can understand your concern.

Looking at your symptoms,you are suffering from Chronic Laryngitis(inflammation of Larynx-Voice Box)
Exposure to Atmospheric pollutants like Dust might be an initial cause.
Other causes which act as trigger leading to chronicity of your condition might be as follows:
Gastro-esophageal Reflux,
Faulty Voice production-Excessive use of voice or speaking in an abnormal pitch like Shouting or whispering,
Allergy,
Viral/Bacterial infection in the nose or throat,
Exposure to dust and other pollutants,
Eating cold food,etc.

You have already shown to an ENT Doctor.If not done before then I would advise you to have Endoscopic examination of your Larynx(Voice Box) to rule out other forms of Chronic Laryngitis which may lead to Chronic Hoarseness of voice like Vocal cord polyp/nodule/cyst which might need Surgery as a treatment.

Also if you have habit of faulty voice production,then it would also be advisable to consult a Speech therapist.He/She will guide you how to use your voice correctly.

You may find relief by taking the following medications:
Analgesic with Anti-inflammatory like Ibuprofen,
Antacid like Pantoprazole,
Mucolytic like Ambroxol(if you are suffering from cough and need to clear your throat repeatedly),
Antihistaminic like Cetrizine.

Also take voice rest for a few days.Speak only if neccesary.Speak softly after taking deep breath.Do steam inhalation.Drink lots of warm fluids.Avoid cold food and dust.

Hope this answers your question.I would be happy to answer if you have any further questions.Take care.

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