I don' t think both the conditions are related. The itching might be due to some allergic condition or fungal infections. You might want to try a course of oral anti histamines
after consulting with your physician, which might help reduce the itching. Allergy
might be due to a particular food, detergents, cosmetics,etc. Find out if you have tried something new in the past 2 weeks and avoid the possible allergen.
The pain in the waist area could be due to many conditions like ovulation pain, appendicitis
, gas etc.
However , it would be best if you could visit your physician and get thoroughly evaluated.
Hope this helps.
Dr. Divya Kuttikrishnan