Sounds like a great sign you should quit! You are young for that kind of cancer, but you may be having other issues like irritation of the esophagus because of smoking. Smoking massively increases your chance of getting cancer and of dying from cancer. Also, it's been proven that anyone who can smell the smoke around you gets exposed and has a higher risk of cancer too. It also makes your face age a lot faster. As long as you can swallow ok there probably isn't a mass (meaning cancer) blocking your throat. Sometimes esophageal irritation can make the muscles that help you swallow not work properly. Stop smoking for a few days and see if it goes away and also see your doc.