Brief Answer:
It's due to inflammation of sound box (larynx)

Detailed Answer:

Hi,

Loss of voice and heaviness of chest is a sign of laryngeal (sound box)involvement due to different causes:
- Infection and inflammation, bacterial or viral, associated with cough, fever and loss of voice or hoarseness of voice
- Allergic reaction to medication, exposure to inhaled allergens like dust or smoke
- Bronchitis or asthma, associated with infection and breathlessness
- Irritation of throat or over use of voice like screaming or shouting
- Acid reflux can have corrosive effect on throat and sound box
- In some cases carcinoma

* Personal care - Give rest to sound box (avoid speaking, hot saline gargles, drinking warm water, avoid spicy and oily food, smoking, exposure to allergens, over the counter anti-inflammatory pills like Ibuprofen or cold medicines like Sinarest
* Evaluation of symptoms ,needful investigation to pin point the cause and specific treatment with antibiotic, anti-inflammatory drugs, proton pump inhibitors ,anti allergic medication as per need in consultation of expert.
Please consult an ENT specialist.

I hope that answers your query. Any follow up query is welcome.
Thanks.

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