You need to wear a face mask whether you have the virus or not, I don’t know who spreads these rubbish rumours about things like ” it’s only for those with the virus”, I wish people would check facts before just posting the same incorrect statements circling social media!
Unless you have been tested for the virus and been given the all clear and since the test not had contact with anyone or anything that could pass the virus on to you then you may be carrying it without any symptoms and passing it on to the unsuspecting public by just breathing, wearing a face mask would greatly minimise this.