When i take a deep breath my breastbone feels tight an it makes me cough feel can't fill my lungs been 2 months started from viral chest infection?

Inflammation: It is not uncommon to have inflammation in the joints of the breastbone where the ribs attached (called costochondritis) for many weeks after a bout of lung infection. However, if symptoms are not abating or are getting worse, you should seek evaluation. Sometimes, the infections have not fully resolved, or a new infection may have taken hold.