The most likely cause is a throat infection; this could be an infection of the tonsils and pharynx.
You can try the following home treatment.
Rest.
Plenty of fluids.
Tab. Motrin (OTC) 200 mg twice daily for the pain.
Hexidine mouth wash (OTC) - use for mouth wash three times daily.
Another important home treatment is Menthol steam inhalation - add Menthol salts (available OTC) to a bowl of steaming water and inhale the steam two - three times daily - this will relieve the congestion.
If the feeling persists beyond three days, or gets worse, you will need to see a doctor for a prescription for antibiotics.
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