sharp pain with exhaling

my 19 year old brother in law has been experiencing pain when he breathes out since he was in the eigth grade..says it comes and goes, and it feels a lot like when you have to make a bowel movement (so i guess kind of like cramping) only in the bottom of his lungs. he's seen doctors about it when he was younger, who told him basically that it was psycological..i have seen him in pain and i have looked online for any answer or clue to point me in the right direction, but i am not familiar with any lung disorders or how to research them..does anyone have any insight they'd like to share? any help is appreciated.