if you could provide information about anything happening before walking to work thirst pace distance temp etc it would be much appreciated. however it sounds like it could be heartburn assuming: you ate a large breakfast with little to drink you ate no breakfast and stomach is refluxing if it is vertical in the dead center of your chest (right below throat ) pressing down on it helps. but without any more information i have no idea.
when i walk to work i get a burning pain in my chest like swallowing a hot potatoes. i am a smoker. what can this be?