Im 17 and im experiencing bad pain in my right side of my rib toward my back, whenever i turn right or left or even sit down at my desk i get a bad pain and i gasp for breathe. it is really hurting.

i havent done any heavy lifting or bad exercise, i work fulltime as a admin assistant so i sit at a computer all day. ive had this pain before a couple months ago but it went away and came back on sunday

i dont know what i should do?  any ideas?