Hey, I have auto-immune pancreatits, which is ver similiar to type chronic type. I'm 23, former college linemen but after I was diagnosed I had to hang alot. Protein shakes and protien n general can be tough to digest but if you must get the lite/low fat versions. I'd reccomend you eat alot if pastas, breads, vegitables, rice,I eat egg white for protien, and skinless chicken breast. I also take creon to aid in digestion. Steps must be taken to prevent any pain. Your chronic heartburn is a symptom of pancreatitis and you should take prevacid or Zantac daily. Working out, is tough when you can't consume the protien you need so I say just work on high reps lower weights and alo of cardio. I find it's a great way to distract from pain. Your back pain is also a symptom, the pain usually starts upper right abdominal area to back and sometimes chest. If you feel nauseas and can't keep anything down, it can be an indicator of a future attack and you should switch to a liquid diet (broths, water, jello). Many dicots may recommend smoking marijuana to help with nausea, it does not affect the pancreas so go ahead, just have some fresh fruit around.
Granted, I have the chronic condition I have to be much more careful, I find keeping a journal of what you eat and pain and symptoms to be quite helpul. Also taking anti-oxidant vitamins is good. Avoid butter, cheese, fatty meats, nuts, cream, anything fatty basically. High carbs will make life easier. Hope this Helps