Good Morning. I Have Such Problem That Oftenly I Have

Good morning. I have such problem that oftenly i have got a loose stool. I thought maybe it may be caused by this that i am eating ksylitol cause its side effect of this kind of sugar, but on the other hand usually i am eating only like 2-3 spoons of it, and additionally i oftenly have pain in the left upper quadrant of my stomach. It is short lasting acute pain which occurs only time to time, and time to time i also have acute pain on the left side of the chest, which occurs during the rest and its short - lasting. In general i dont have any systemic disease except food and pollen allergies which lately cause atopic inflammation of the skin. SO i was wondering if those symptoms may indicate some diseases of pancreas or spleen? WHat kind of tests should i perform to get more informations?