Hello and welcome to HCM, A sudden terrible pain in the chest region can occur due to many reasons. Angina pectoris, esophageal rupture, aortic rupture, Bohaerve syndrome to name a few. Associated feeling hot and cold can be due to sympathetic over-activity. Sympathetic over-activity can occur in any of the above mentioned conditions. Esophageal rupture or aortic rupture are medical emergencies. Patient usually collapses after suffering from any of these conditions. So, there is very less possibility for these conditions. Angina pectoris is most probable. Angina pectoris can occur at rest also. You need to get some investigations done. A X-ray of chest and ECG are the first line investigations. Any abnormality of the cardiovascular system will be picked up. Further Holter test may be required. Consult your physician for further work up. Thanks and take care Dr Shailja P Wahal