Itchy chest/lung

Hi i am 29 years old and a recent ex smoker. (smoked 6 a day for about 10 years)  I have mild asthma and only ever use my inhalers when i have a cold or the flu.
A few weeks ago i was diagnosed with a chest infection which has cleared up but now i was told i have costochondritis the pain is at the top of my right breast bone. I don't know what the symptoms are for costochondritis or why/how my gp diagnosed it.
Lately i have been experiencing a weird itchy feeling deep inside my back in the the area of my right lung. I have experinced this a few times before even when i was younger ( about 16 yrs old) however it is happening alot more and i am very worried as to what it may be.
Can it be due to the costochondritis or is it due to the mild asthma i have? I am so scared that as i am a recent ex smoker that it may be a symptom of lung cancer? Please help rest my mind a little.
Thank you in advance

[National Jewish Health]

Costochondritis occurs in the areas where the bony ribs become cartilage and attach to the sternum, which is the long flat bone in the middle of your chest, overlying the heart.  These junctions can become inflamed following blunt trauma, surgery or hard coughing.  Costochondritis usually resolves spontaneously but the pain can often be relieved by taking a non-steroidal anti-inflammatory medicine such as ibuprofen or naproxen.

It is highly likely that the "itchy feeling" is a skin phenomenon and not a sign of serious internal body disease.  Given that you have asthma, it is most likely to be on an allergic basis.  It is not a sign of lung cancer and the likelihood of lung cancer in an asymptomatic, seemingly health 29 year old with a history of light smoking history, is infinitesimal.

[sb786]

I don't know if you will see this but sorry i forgot to mention that apart from the burning sensation and pain due to the costochondritis i have no other symptoms such as no cough, no wheezing etc.
Thank you