my dad had a shadow in his lung following months of chest infections which anti-biotics couldn't touch. he also had a bad cough, a loss of voice (on occasions) and a funny whistling noise when he breathed (worse when he slept).
he was told that the shadow could be old scar tissue from when he had pneumonia as a child, but he was referred urgenty for a pet and mri scan (at different hospitals up and down the country)
He was 64. It was lung cancer :(
he had his lung removed, was out of hospital within a week. walked to keep fit and get his other lung working enough to substitute fo the missing one, and had follow up chemo to get any cells that had spread (3 months worth, low level - made him tired but not incapacitated)
4 years on, he is still clear of cancer - he does have recurrent problems as a result of the operation, including a weak arm where the muscles were cut through, a lingering wheeze (currently being investigated, though no medics are concerned it is cancer) and is medicated for life due to severe reflux (things sifted round inside when lung removed meaning he suffere quite severely months after the operation.
I still worry for him, particularly as he is wheezing. I still remember the fear and trepidation - BUT he IS fine, and I truly appreciate all that I have in my life, as this really brought home to me, how quickly it could all be taken away.
Despite being a very robust person, these memories, and sharing them with you, have brought me close to tears, at the thought of going through all of that fear, uncertainty, and desperation again. I really feel for you.
I will answer any questions I can. Please feel free to ask.
I really hope for you and your dad's sake that is is not lung cancer, but if it is, know that the outcome can sill be good, despite the statstics (i strongly suggest not googling)