What Causes Weight Loss, Constipation And Pain In The Legs?

Female, age 63, Caucasian, with: Unintentional weight loss (since last summer 36 lbs down from 154,)loss of muscle tone & mass, elevated creatinine, intestinal pain/burning, rest pain in legs (severe about 4 weeks ago). Typically constipated to chronic constipation over last year. Ultrasound, colonoscopy, upper gi all normal. No diabetes. Lactose & gluten intolerant. Celiac & crohns testing underway. Started last summer went to gluten free low car, sugar free diet. Stabilized 4 months, flared up after some sugar consumption, stabilized 3-4 months with looser greaser floating stools, & flared again this March after sugar carb consumption. When stable weight gain occurred & muscle tone improved due to training. Each flare up typically seeing daily weight loss of 1-1 1/2 pounds.