Have you ever discussed possible vitamin deficiency with your doctor? I was looking online for the symtoms you're describing and found this among other resources:
Riboflavin deficiency has profound effects on the metabolism of carbohydrates, fats, and protein. All three of these basic food elements require riboflavin if they are to be properly utilized by the body. A deficiency of vitamin B2 (riboflavin) may result in bloodshot eyes, abnormal sensitivity to light, itching and burning of the eyes, inflammation in the mouth, a sore and burning tongue, and cracks on the lips and in the corners of the mouth.
Just a thought.