Sore throat need advice

Hey doc I'll try to make it short around 2-3 months ago I started to feel something stuck in the back of my throat. It would fade away when I ate, it felt like there was a little ball stuck back there everytime I would swallow my saliva, it would also get worse when I smoked. A few weeks later it resulted in a really sore thraot still accompanied with the feeling of a lump stuck back there. I went to my Doc a month after this all happened and he did the regular check up, like check up and felt my neck and also looked inside my throat and said that I have some post nasel drip but not to worry. He gave me a 7 day course of antibiotics, i think it was Biaxin xl 500mg a tab or something like that, my sore throat got better but didnt fully go away, and the lump was still stuck back there. A month after that I went back to him which was a few days ago and he gave me a 10 day course of the same antibiotics and its been 4 days since I started taking them, I'm hoping it helps. my questions are
1. Do you think that I have anything serious like cancer or a tumor or something along those lines?
2.If in fact I have post nasel drip could my doctor tell without any tests? WOuld the antibiotics help get rid of PND? What are the best treatment to get rid of PND?
3.Im going to an ENT in 10 days what tests can I take?
4. I know you cannot diagnose online but with your knowledge what would you say I may have, hopefuly nothing serious?
Other than that I am a pretty healthy 25 year old male. I quit smoking about 30 days ago, so I dont think its because of that Thank you so much in advance.

[National Jewish]

The most likely cause of this symptom in a healthy 25 year old is anxiety, so called "globus".  It might be related to the smoking cessation.  The most important thing to do is to rule out a physical or organic cause.  This is best done by an ENT specialist exam, maybe with imaging (MRI) of the neck.
Postnasal drip is mucous from the nose and sinuses dripping down the back of the throat.  A nasal wash helps remove mucus from your nose and sinuses.  It is most helpful when done daily before using any nasal spray.  A prescription nasal steroid spray decreases mucus production by decreasing the inflammation of the nose and sinuses.  This may prevent the postnasal drip.  A nasal steroid spray does not provide immediate relief of symptoms.  It may need to be used every day for several weeks to months for it to help.  Please read our Nasal Wash MedFact at http://www.nationaljewish.org/medfacts/nasal.html for more information about this technique.