27 year old female, 5'6, " 262.4 lbs, ekg: normal, holter monitor (48 hours): normal, cholesterol: ldl- 111, hdl- 49. Chest pain related to heart?

Chest pain. Not enough data for more than a guess. Its probably not cardiac related, BUT, you are at increased risk. You are morbidly obese and weigh roughly 100 #s more than you should. Each pound of flesh equals about a mile of blood vessels. So, your heart, a pump the size of your fist has to pump blood 100 miles further than it should. If you smoke, use illicit drugs or drink the risk is higher.