I am a 20 year old male and I am experiencing the exact same problem at the moment. I have had an uncomfortable feeling in my left brest area for a while and in my left shoulder blade,its not a sharp pain just a nagging discomfort.
I had a sudden anxiety attack about it in work two days ago assuming I had some terminal illness like lung cancer and had to leave work immediatly. My doctor did a basic blood pressure test and listened to my chest. He said I was fine and it was probably due to anxiety.
Unfortunatly it does not make me feel any better as it is still there and I have been experiencing fatigue since I had the anxiety attack and I find today I am quite irratable and don't want to deal with anyone I am also experiencing also shortness of breath. Im still worried but it helps to know others are experiencing it too.
These are very common and nonspecific symptoms. It is best to discuss these symptoms and your concerns with your physician. He can perform tests and go over them with you to explain the problem or to reassure you that all is OK. Trying to do this over the Internet is impossible and can only lead you to more anxiety.
EXERCISE,YOU ARE EXPERIENCING ANXIETY,AND DEPRESSION,TALK TO A GOOD THERAPIST AND START A RUNNING ,LIFTING PROGRAM AND YOU WILL BE AMAZED AT THE RESULTS AND THE ABILITY TO SLEEP AND DEAL WITH STRESS,I HAD THE SAME PROBLEM WHEN I WAS IN MY TWENTIES AND BEAGN AN EXECISE PROGRAM AND THE ANXIETY WENT AWAY,I WOUND UP RUNNING MARATHONS AND SOLVED ALL MY DAILY PROBLEMS DURING THE RUNNING TIME ,PLEASE TRY IT