GERD (gastro-esophageal disease) is a condition when the acid of your stomach flows back to your esophagus. the lining of our esophagus is not the same with the lining of our stomach, that s why once the acid goes up to the esophagus it will usually manifest as burning sensation (because it is an acid) in the chest radiating to the back, and most of the patient will complained of upper back pain ( that is because of the anatomic location of the esophagus directly adjacent to the spine). it usually starts when you eat a spicy or sour meal and beverages, if you just drink coffee/ tea/sodas, or you skipped meals or had eaten your meals late, or STRESS. once the acid goes up to your esophagus and you fill the burning pain in your chest, normally you will be anxious which can be manifested as palpitation, in palpitation your heart beat faster than normal, which results to shortness of breath because unconsciously you will also breathe faster which will result to blowing off of your carbon dioxide in the body which is supposedly responsible for the relaxation and stimulant for respiration... as a result there will be numbness of on your extremities and further shortness of breath. treatment is simply avoidance of the foods and beverages i mentioned earlier, reduce stress, and you can used proton pump inhibitors or ranitidine to lower down the acid.