I am not a doctor and I have no medical qualifications.

This sounds like a typical reaction to a throat infection.  The neck and throat is a mass of small lymph nodes, often simply called "glands".  There are more node under the arms and in the groin, but they can be found in most parts of the body. They swell up in reaction to an infection - inside the node a small scale war is taking place as it marshalls the body's forces to fight off the invader.  Often there are no other symptoms, apart from the swollen nodes. 

While the node is fighting off an infection, it will usually be painful and swollen.  Most of the time, the node will subside after a day or two.  Sometimes it will take as long as 4-6 weeks before it settles down, and occasionally a node never returns to normal, but instead remains harmlessly swollen.

The general consensus is that you shouldn't even begin to worry about a gland until it's been swollen for about 6 weeks - and even then, the chance that it will be cancer is very slight.  However, if you start to suffer from symptoms such as drenching night sweats then you should contact your GP.   And of course you should use your common sense - if your symptoms get worse or you start to get really worried, then contact your GP.  

I noticed the same thing when I was 17, the doctor could feel it too, I was sent to the hospital where they told me it’s just a normal gland and sometimes when you have sore throat it swells up but doesn’t completely ever vanish. My one is under my chin too.