I agree with the others...see a doctor. An occasional irregular heartbeat (arrhythmia) is probably normal and might be caused by certain stimulants such as caffeine. But if the irregularity is too often, you can become at risk of a stroke. Regular pumping of the blood is necessary to keep your arteries clear. When the pumping becomes irregular, clots can accumulate in your arteries...you want to avoid this. I get occasional arrhythmia also, but it usually manifests itself in a few (light) coughs, not a difficulty in breathing. For the pain in chest and difficulty in breathing, you might also want to check if you are experiencing acid reflux (heartburn). Heartburn, as its name implies, will often NOT feel like a burning, but like a heavy pressure on or in your chest.