I am 18 years old. i have been having chest pain for the past week and i went to the emergency room twice to diagnose what wrong with me, my ekg, x-rays, blood test and urine test came out great and they said nothing they couldn't find what was causing

Chest xray?: Did you have a chest x-ray? It would make sense that among all the other tests you mentioned they would have done a chest xray to r/o a pneumothorax or a pneumonia. It is possible this is reflux, so you can try some antacid like Tums (calcium carbonate) to see if it helps. Another possiblility is costochondritis, an inflammation of the joints between the ribs and the breast bone. Usually ibuprofen helps with that