Hello dr, i just started cardio workout yesterday at home, and now i am having pain in lower side stomach,is it normal or i stop doing this.

Not likely cardiac: First, it's good that you are embarking on taking good cardiovascular care of yourself, but the symptoms you describe are more likely to muscle strain than anything worrisome, especially since you just started this. Dial back the intensity after resting a few days, and only GRADUALLY ramp up the activity (week or two at any given level). If the symptoms recur, talk to your own doctor to be safe.