What dose it mean when you have pain under your left rib

Your brain is sent signals that tell you have pain and that you should get help.

These are all i could think of

gas stuck in colon
irritation of the spleen 
broken rib
acid reflux
heartburn
stomach ulcer
irritable bowel syndrome
kidney stones
pancreatitis

What kind of pain is it? Abdomen or back?

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)