Breathlessness after exercise, not getting better with time

Patient: HiI have shortness of breath when I exercise just a little, like jogging 1.3 km. At first I thought I was just unfit, but it doesn’t get any better after 2 weeks of jogging. I went to the doctor who did a lung test on me, it seems I am very bad at inhaling, although my exhaling is fine. She prescribed Oxis formoterol and Foxair Accuhaler to me. I’ve been using it, but still no results. ­čÖü I am still struggeling with a mere 1.3 km run. Please help. What can I do to battle the breathlessness? What else can I do to improve my fitness? (I am 23 years old, athletic built, not overweight, female)