i suggest you return to your health care provider for a re-check. you could be experiencing a new illness that's unrelated to the sinus infection. or perhaps it wasn't a sinus infection after all but a virus that has now gone down into your lungs. regardless if you're having trouble breathing it's worth getting checked out. hope this helps! breathing problems after upper respiratory infection are common especially bronchitis and asthma. but you need to visit a doctor to confirm the cause and diagnosis so that proper specific treatment is initiated. most probably you may be suffering from bronchitis.
recently developed some breathing issues and have a soreness of lungsany possibilities. have had sinus infection recently but got over that but about 2 weeks later started having trouble breathing. no cough no injuries