Hi and welcome to the forum! I am glad that I can help you.
You would like to know the cause of the symptoms that you experience.
Acute pancreatitis may develop into chronic pancreatitis, pancreatic cyst, etc. Chronic pancreatitis is characterized with constant pain in the abdomen and the upper right side, which may radiate towards the shoulder blades. Individuals who experience pancreatitis may later develop diabetes melitus as a result of destroying or forming fibrous tissue in the part of the pancreas responsible for production of insulin. Hypoglycemia may cause tiredness and weakness. Pain in joints and bones may appear due to rheumatic conditions (often in elderly people) or due to metastasis in certain cases.
Given the data that you described you may be experiencing chronic pancreatitis. You may need to have a blood count (especially blood sedimentation) and laboratory tests such as glycemia. You may also consider having an ultrasound of the abdomen to rule out any condition related to possible tumor ingrowth.
Please keep in mind that I provide medical information only. I am not able to diagnose medical conditions online. Please contact your doctor for further advice and information about diagnosis and treatment options.