From last 15 days I first had Productive cough and sinus issues then it gradually decreased I was taking cepfodoxime protexil antibiotic for last  10 days because of my Dental molar teeth infection... Productive cough resides.but now have episodes of Dry cough with minute amount of white mucus expelled out every time cough but while coughing Chest produces mild  barking and wheezing while forceful experetion of air from lungs .So decided to do a Chest Xray today ...Now I am Mbbs student and X ray show a whitish part  near left side of Heart and mediastenum what is it ...Is the Chest xray Normal i am very much anxious about this now...I have given the the Xray and also encircled the part which is my query is that normal structure of heart or vessel or else? Please Sir or Mam tell me I am very anxious