You could be lactose intolerant. Keep in mind that NATURALLY AGED CHEESES are lactose free because the bacteria eat all the lactose within 60 days. So fresh cheeses like Cottage Cheese, Mozz or Chevre are out for lactose intolerant people. A lot of the big companies cheat by using chemicals and enzymes to accelerate aging, so store bought cheese CAN have lactose. Many doctors are uninformed and will simply tell patients not to eat cheese - WRONG.
You could also be sensitive to casein protein.