X-Ray was normal - this DECREASES the probability of it being a lower respiratory tract infection like pneumonia. The docs at ER must have also searched for murmurs or other signs for endocarditis and have found none - This was probably the reason why the ER ppl didn t ask for any more test. Trust the clinical skills, tests aren t always necessary ! However in view of the septal defect in your baby, I would advise you to meet some pediatrician.Fever with no apparent cause, itself mandates further investigation but not necessarily emergency care. Another thing , pain in chest doesn t always mean that that cause is some heart trouble so don t panic (panic wouldn t help anyway !). It can be because of some respiratory condition or even acid regurgitation disease (this what I had thought of initially , but it can t explain the persistent fever). So all u need to do is to take your baby to a doctor you believe in .Just tell the symptoms , show the X-ray film and inform of whatever happened at the ER.