Feeling like squeezing in heart/chest can be stress/ anxiety or panic attack
related. Smoking/ caffeine intake may also cause it. As you have stop it and your Chest CT scan , Chest X-ray , blood tests and EKG are fine(normal), you need not worry for having any heart disease
. Panic attack usually causes Palpitations, increased heart rate
, Sensations of shortness of breath
or being smothered, Choking, Chest pain or discomfort.