If you and others can hear the wheeze it is real, despite the fact that it was not present on the physician's examination, and should be evaluated. Wheezes often come and go and even persons with asthma do not wheeze all the time.
Your doctors should determine if the wheeze is coming from the upper airways (
noseNose fracture, throat, larynx) or from the lungs themselves and, if from the lungs, is it coming from one lung or both. That your chest X-ray is essentially normal for your age and shows no cause of a wheeze, is good news.
The best thing to do would be for you to ask your doctors to refer you to a lung specialist, to evaluate this wheeze.