Full cardiac work up normal.last couple days my hr has been good over 100bpm when standing. cardio&pcp said it's from being inactive&stress.this true?

Possible: I am sure that you had work up. Possibilities would include hyperthyroid, anxiety, obesity, but I would exclude pulmonary embolism, especially if you had travelled, and/or having family history of it, blood clots or miscarage. Other pulmonary causes also possible, but I would get PE excluded well. Also, may need Holter or Event monitor to reveal some arrhythmias

BP HR: Normal HR 60-110. If you are sedentary, chances are your cardiovascular system is deconditioned in which case you will have an elevated HR with minimal activity.