White scaly patches in the inner folds of my skin near the butt area. It itches and some pain from scratching. Do I have jock itch? I am a female.

Intertrigo. Not related to diet. Try OTC hydrocortisone and miconazole ( or clotrimazole) creams together. Whenever it feels wet or itchy or irritated,gently clean off with bathroom paper (or kleenex) using any lotion. In the shower, wash with hands only, no scrubbing.
Candida. Candida or yeast can certainly create these symptoms and presentation. You can get a prescription from your doctor. In the meantime, cut out all sugar and yeast from your diet, keep the area clean and dry and you will start to feel better.