Difficulty breathing doing what I did about 2 years ago without problem. Age or sedentary effect?

Not age, disease. Aging and sedentary lifestyle certainly lead to problems. Aging, not as much as people think (proper lifestyle of living, eating, resting and working will dramatically limit aging affects); sedentary lifestyle much more problematic. But if the same activity you did 2 years ago is causing difficulty breathing, it is a heart or lung problem till proven otherwise. Get ye to a physician.