24 yr old not an athlete male.bpm at rest is usually on low 40s, got an echocardiogram and a stress test & normal.. im scared should i worry?

No, not yet.: Those who have made a habit of exercise & are very fit often have low resting heart rates (in the 40s, sometime the 30s). If you are NOT fit, & a resting heart rate this low, you must have symptoms. You could have an underactive thyroid, high blood pressure, or other chronic condition. Talk to your doctor & get checked out with an exam & blood tests (if needed) to get to a diagnosis. You have time