My Boyfriend Has Had This Stomach Ache For Two Days..

My boyfriend has had this stomach ache for two days.. Sometimes he's fine but other times he just wants to lay down because of the pain.. He also is experiencing hot and cold flashes and barely touched his dinner.. No fatigue.. But he did say that his stool was a bit harder than regular.. Yesterday the pain was above his belly button but now it's just like pain all over the stomach. Hes not nauseous but i wanted to check for appendicitis and pushed on his left side to see if his right side reacted in discomfort or pain but he said there was no pain.. What else could it be? And when should we seek medical help if the pain doesnt stop?