Does groundglass opacity in upper lobe on ct mean it's a lung nodule or not?

No, a lung nodule is different and would be stated as such. Ground glass opacity is a non-specific finding that indicates the presence of inflammation and an etiology for the inflammation would need to be diagnosed. If it persists, a bronchoscopy to biopsy the area is often needed to make a diagnosis as to etiology of the inflammation. So, see a lung doctor for evaluation.