Hello and welcome to HCM
Alone EKG cant say that you have no heart related problem. In chest pains we have also to know about Heart enzymes values. As it seems that you have no chest pain now but still at your age you have to go through a complete heart checkup(EKG, TMT, ECHO and lipid profile
with fasting blood sugar) once in a year.
Now related to your problem i.e. leg swelling and heaviness, it might be due to Diabetes mellitus
(don't know your history), Spine related problem like PIVD(common at your age), straighten Lumber curvature etc or due to over weight or even in some heart related problems. You needs to be investigated for this.
Consult your doctor and get your check up done and get to a diagnosis and take related treatment.