The chances of a teen getting something like throat cancer? I've been to the doctor?

The most important thing for me to rule out, is I'm nearly 18, I've never smoked in my life, I only drink 2-4 glasses of wine on special occasions, which is every two months or, I have my vitamins and minerals (thanks to my very healthy parents), and lastly, I live in a major city (London). Now, after having 2 colds since March, it has come to my attention that for 2 weeks, I've had phlegm dripping down my throat, a sensation of phlegm stuck in my throat and now I have chest pain when coughing and it feels like I'm being choked by my own airways. I've been to the doctor, I've had a full examination of my throat and breathing, and I've been told that it's either a cause of stress or simply something viral. I've HAD a blood test and the result came 5 days ago as I'm writing. The doctor prescribed my drugs that will remove the phlegm, it's helped a little, now came back. I still have these symptoms, but somethings come to my mind and the scare is because in 2013, my aunt died from lung cancer. Obviously I don't feel anything with my lungs, it's the throat that's bothering me. So, chances of me having throat cancer?