What Causes Burning Sensation And Pressure In The Chest While Running?

Question : starting about 9 months ago I had a burning sensation and a bit of pressure on my chest when I ran. I would stop running for 5 or 10 minutes, then proceed to run again with no difficulty. It got bloworse. In January I called the doctor's office to tell them the discomfort in my chest. They told me to go to the ER. At the ER they took chest e-rays, did an ekg, and lab work. All was normal. They recommended a cardiologist. I did a chemical stress test which was negative, an electrocardiogram which was negative. Later he did an angiogram and found a 75% blockage of one of my arteries. He put in a stint. After I was cleared to exercise, by original symptoms have stayed with me. It seems to me the cooler the air temperature, the more acute. It seems to be getting worse. I have also had an endoscopy. It showed some irritation and a medium hiatal hernia (I have acid reflux). The gastroenterologist said that because the esophagus and trachea are so close together, the burning sensation could be the result. Antiacids have not had any effect. Lastly the pain I feel is usually the first half of the day. Generally by the second half I am free of this tight burning pain. I am very frustrated that no one has pinpointed the problem.