Severe pain in your midchest that comes suddenly and lasts for couple of seconds, is result of esophageal spasm or uncoordinated muscle contraction of esophageal wall.
Chest pain is a common symptom of esophageal spasms.
They can lead to chronic swallowing problems and may be treated with certain drugs that will lead to muscles relaxation.
One of the reason for the spasms is consumption of very hot or cold food or drink.
Avoid hot, cold or spicy foods, large meals, or foods with a high acid content.
For your sore throat try gargling three to six times in 24 hours with warm salt solution.

Best wishes!
Marija