2018-03-24
Your body is a castle. Germs are invaders. Your castle has thick walls but needs gates so you can see out of it, take in supplies and get rid of rubbish.
Gates are weak spots so get attacked more often. The throat is the most open to attack as it is moist, warm and we are constantly moving air (containing viruses/bacteria), food which we have touched with our dirty hands etc. across it.
The throat releases chemicals to make it swell up to deliver more blood (and therefore more infection fighting cells, nutrients etc.) to the site of attack. Swelling causes pain, presumably to make us go easy on parts of the body which are under attack.