I'm 23 and my heart is always beating harder than normal. Often feel SOB and cant get a full deep breath of air when exercising. Doc. Cant figure it out.

Echo? Have you had an echocardiogram? Do you have valvular disease (AR and MR) which can cause excessively high ejection fraction? Do you have an elevated pulmonary artery pressure which might correlate with exercise hypoxia? Have you had a pulmonary stress test: treadmill exercise measuring your oxygen saturation. Spirometry with methacholine challenge? TSH, CBC, BNP? Chest x-ray?