Had a ct scan 6mm lung nodule they said nothing to worry about is there any chance that the ct could have missed a tumor that maybe causing chest pain?

Yes, Kind of.: The answer to your question is complex. Most lung cancers don't cause chest pain unless they advance into the chest wall. 6 mm is near the detection limit of a CT scan (small). However, it still could be malignant (cancerous). Your risk depends on its location, whether you've smoked, its appearance on CT, other factors. https://reference.medscape.com/calculator/solitary-pulmonary-nodule-risk