Male 33, had a bad flu / virus unknown reasons went to doctor later on because of blood spitting, ct scan found nothing, no blootclot in the lungs, chest x-ray done nothing found, what is causing this? i'm not sure anymore. bronchoscopy coming soon?

Blood in sputum when coughing (hemoptysis) is NOT UNCOMMON in acute bronchitis. I am not sure why bronchoscopy is indicated if chest X-ray and CT were normal unless your blood test results have revealed some hints for certain diseases which require bronchoscopy although CT was negative. Good luck with your next test.

Following infections involving airways, sinuses and/or throat, hemoptysis or blood in sputum is relatively common, there should be a reason for why your physician is trying to determine the source of the bleeding. A thorough ENT exam will be also needed in case the bronchoscopy remains non diagnostic.