Just because nothing showed on the test does not mean you are not having cardiac issues. One big problem with doctors and tests is that they don't see what we do or go through in our NORMAL daily routine. Like a car that doesn't act up when you take it to the mechanic. Is the foot swelling just the right leg or both? If just the right you may have a circulation problem in that leg causing pain and swelling. Be on the look out for redness and warmth that may indicate a clot. A plugged/sluggish lymphatic system can cause swelling as can poor circulation. If you have vericose veins/spider veins this si a symptom of incompetent vein valves which can lead to swelling. Pitting edema is caused by extra fluid in the tissues. Some causes are heart, kidney and liver problems, too much salt, low albumin. Some women are just more prone to unknown cause of edema. Usually heart conditions, mainly congestive heart will cause swelling in both legs. Are you on diuretics to remove excess fluid? A restricted salt/ sodium intake diet?