<s>[INST] severe left upper abdominal pain that goes through to the back. oily loose stools 10 to 15 a day. chronic fatigue, muscle and joint pain all over. Pancrease levels over the last few years are one time way to high and the next time the levels almost don;t exist. [/INST] Hi, Welcome to Chat Doctor. I have read your query and understand your concern.It's due to pancreatitis only. The pancreas enzyme peeks at the onset and then fall back rapidly over a couple of days. So the levels are not used to monitor the disease progression. The oily stool is due to fat indigestion. You need to take pancreatitis enzyme supplements and avoid fatty foods.Also, Chat Doctor.  Fatigue and pain can be due to anemia or electrolyte imbalance. So you need to see you local doctor with the above reports for the same Hope I have been helpful. </s>