I get a recurrent achy pain on the left side of my abdomen (underneath ribs). what could this indicate? it happens at random times

Bowel,kidney,spleen.: Not many things here: the colon makes a sharp turn and is often postulated to cause cramping or gas type pain, the kidney is there, but pain is typically more constant. Spleen also - pain is not usually "random." muscles of the abdominal wall at the costal junction can also cause this. A brief exam could help localize this.