I am spitting up brown mucus

I quit smoking a little over 2 months ago.  I wasn’t a heavy smoker, maybe 3 to 4 cigarettes a day, but started fearing lung cancer.  I have had back pain for quite a while on the right side of my back and occasional chest pain on the right side as well.  Also, when I twist from side to side, it is as thought air is being compressed out of my lungs; I can feel air being pushed out.  I had a CT Scan of my chest done 2 weeks ago and it was clear, but I have been spitting up blood the past couple mornings and have had these brown speckles in my mucus as well.  Should I be concerned knowing my CT was clear or can there be something else wrong?

[Dennis MD]

Hi.
I commend you for already quitting smoking.  Smoking is a risk factor for many diseases, including heart and lung diseases as well as several cancers.
It is possible that the blood you see when spitting is coming from the oral cavity or throat, especially when you are forcefully coughing.  However, if this persists, you need to go back to your doctor for re-evaluation.
Good luck.