Brief Answer : Coronary Artery Desease Detailed Answer: Hello and thank you for question. I read very carefully your concerns. The sensation of heart squeezing followed by numbness of the left arm, in mos cases is caused by a problem of the heart vassels called coronary arteries. Usually the problem consists of their blockage due to atherosclerosis plaques that block. the blood flow inside of the artery. In this cases the muscle of the heart it is not supplied with blood and oxygen,wich casuses the death the cells of that part of the muscle. If that blockage of the artery persist for a long time, there are great chances of ireversible cell damages. In this situation it is better to ask some more specific questios like: for how long do you feel this symptomes? How did they start? What you were doing when the sypmtomes started? Do you have difficulty in breathing? Do you suffer from any chronic condition, like diabetes etc? First thing i would recommend to do an ECG (electrocardiogram) and a heart Echography. Also to do some lab test like cardiac enzymes and a lipid panel. Please feel free to ask any other further question. Best regards!