When I walk - even slowly, my veins will get large in my hands. My arms hurt from my wrist to above my elbows. My chest hurts, burns. It burns through to my back and my breathing is labored. My heart feels like it is having a spasm - jumps. What is happening? I have tried to increase my exercise and work through the pain. If I walk for exercise it hurts like this for about 10 to 15 minutes then mysteriously disappears. I can walk for over 3 miles without any discomfort if I can get through the first 15 minutes.