My mom, 68: many years constant hunger, tremor, elevated heart rate, constant lightheadedness, agitation, obsessive thoughts, anxiety, low energy levels. whats the cause?could it be connected to pancreatic gland?always needs to have food with her?

Yes, hypoglycemia or low blood sugar among others may cause such symptoms, discussing it with her doc would be best as she may benefit for having meds adjusted or having diagnostic work up if needed. Severe anxiety disorder may as well be present.

I think the best workup here would be accomplished by an endocrinologist as well as an evaluation by a mental health professional. Constant hunger may be a psychgenic disorder such as depression but medical causes have to be ruled out also.