Suspected Chest infection

Before I ask my Question this is my History. I am male 57 years and a former heavy smoker of 30 years. I Quit 5 months ago.
Symptoms are: some intermittent severe chest pains. Again severe mid to upper back pains especially to my left side within the ribcage, these become pronounced when my back is unsupported for any length of time. No appetite. A month prior to quitting smoking I coughed up huge volumes of green phlegm which continued into the second month after quitting. Still have some nasal green discharge in terms of phlegm.
Had a recent chest x-ray which I was told is clear. I also sweat from my brow very very easily. Blood tests all came back as normal as well such as U & E Kidney and LFT.
All this has brought me down mentally as unable to work with the emaciation, so have been treated for Depression by my Doctor, who believes that my symptoms are Depression-based rather than the other way around. My symptoms described above have nothing to do with my own form of depression.
Any possible solutions please or thoughts on my problem. Thank you