sir, your son might be suffering from acute anxiety. just evaluate once if he has anything to bother with and you don t know. because at this age usually pain in chest and breathless can occur only due to that condition. lung or cardiac condition is unlikely. but without an examination, I cannot surely tell you what to could be exact pathology here but hearing your history I can tell you that its more of mind problem rather than body. go psychiatrist for further treatment.Hope this info helps you sort out your problems. if you feel it is the helpful kindly give user thank vote for me. happy health.