What Cause Shoulder Pain Followed By Breathlessness?

hello doctor , I had pain in shoulder for 2 days , then yesterday morning i had breathless and acute pain , i visited to cardiology , ECG was normal and 2D Echo was normal but troponin level was 0.06 , at present doctor has told to take betablocker and aspirin for one week and told to reconsult . is this normal or something serious . Also note i have taken sildenafil 15-20 days back . I am 33 years of age .