Doctor said that lung nodule i have is calcified, and due to old glanulomatous disease, how do i know if this is right ?

Try 2nd opinion: Calcified nodules are a relatively simple diagnosis either by chest x-ray, or even more reliably, by ct scan. If you have any doubts, get a referral to another radiologist for a second opinion. There will usually be a charge for this, but if it puts your mind at ease it will be worth it.

Time: Calcification is common for granulomatous disease( old tuberculosis, or commonly histoplasmosis in the mid usa. Or other fungi). Sometimes there are multiple granulomas. Cancer can occur near an old scar. If one has had multiple x-rays over the years that is helpful and confirmatory. Absolute proof would require surgical removal and that is a waste.Get a second opinioa thoracic surgeon.

Option: It's very possible that the radiologist who interpreted your chest x ray, assuming there was one, could convince you that there is no practical need to carry this question further.