I have a mole on my back , im afraid its melanoma , and im afraid that its spread. i did x-ray of my back and chest, will it show if there is melanoma?

Maybe.: Xray is very insensitive tool to check for spread of melanoma. Best prognostic indicator is the pathology report which gives a lot of info about the lesion. Why did you get xr if you did not know it was melanoma? Seems like a waste of money and time.

Need to see a doctor: The xray will probably not help. You need to have a doctor skilled at identifying and treating skin abnormalities look at the mole. Your best bet would be to see your primary doctor or a dermatologist. Is there something about this mole that has you concerned? The american cancer society has some good information about skin cancer: http://www.Cancer.Org/cancer/skincancer-melanoma/overviewguid.

Biopsy: The first step would be to biopsy the lesion to see what it is.