My child brother go to the doctor and they said one chest side is bigger?

what are the symptoms towards ?My child brother go to the doctor and they said one chest side is bigger?
In the first 4 yearsof life, its middle-of-the-road to have some assymetries of the body, that correct themselves next to plain normal growth...
The substantial issue here is...how different is one side from the other..?
Did they perform some X rays to check lungs and heart?
If they perform none, relax,,,,that means that the assymetry (one side of a region of te body of different size) is zilch to be worried about,.....or is with the sole purpose a commentof some incidental and non meaningful finding....
It could be anything, not a soul here can tell you, am sorry