I also have been having similar symptoms, haven't figured it all out yet, but several things have helped. One is elimination diet, removing eggs in particular, but also dairy. Treatment for bad duodenal ulcer, and seeing a chiropractor for ribs. Often this can be caused by multiple things. Good luck.
Started Primal June 2012 at 148.5lbs, and 5' 1", reached goal weight in 5 months.
Lowest weight 93lbs - too thin. Now stable at 102lbs much better weight for me at my age.
Primal, minus eggs, dairy and a myriad of other allergens.