Form a triangle from left collar bone, to nipple, to sternum. brief, painless, squeeze that seems to pulse in center of that triangle. cardiac?

Panic or Anxiety: Nope. The most common bizarre (from a medical staff standpoint) is the number of young people who are sure they are having a heart attack and go to the er. First, most brief 'twinges' are muscle spasms in the ribs or sternum. Second. Having heart burn leads to esophageal spasm at times. Then the next is fatigue or stress causing anxiety or panic. Cardiac would be so far down the list.