Hi ! Last week I swam for only 20 minutes around 3 pm. At 6 pm.I started to have pain on my left shoulder. I thought because I carried too heavy shoulder bag. The pain stayed until 9 pm. After that the pain getting heavier. That night I could not sleep all night because the pain on my left arm. It stayed until morning. I am wondering what cause this pain. This is not the first time. I had pain several times on my left arm. Do I have to see a cardiologist ?