Diagnosed with chronic bronchitis, constant dry cough and dysnea, high pulmonary blood pressure, but my lung function tests are normal. Why?

Something else. Your symptom maybe due to another condition other than a lung condition. The elevated pressure in the pulmonary circulation in a young female suggest a condition called idiopathic pulmonary hypertension.a condition with no known cause. However a thorough clinical evaluation is required before this diagnosis is made. Need to consult a pulmonologist and/or cardiologist.