I'm a 25 year old female, 5ft 8 inches and 12st2lbs i recently took up running/fast walking on an evening, i have asthma so i have to run in bursts because i get a pain in my right lung otherwise. I'm an active mother, always walking with my son and playing. After taking up my running/fast walking for an hour i have found in the evenings i have been getting relentless heart palpitations which cease once i have gone to bed. They've now begun to hound me during the day, i'm having them as i write this, what is the problem?