I have irregular itching on my my thighs and sides. What should I do?

Itch. Could be hives but could also be irritant dermatitis from the fabrics or the detergents or soaps....But you should have it everywhere if that were the case. Likely hives. Simple initial treatment is otc antihistamine and possibly some anti-itch creams.
Is there a rash too? Dryness is a common cause.. Try to see if there is a pattern with washing or work or? And if there is a rash take a picture... Then if using mild soaps and daily moisturizers doesn't help(& you have no other symptoms) see your dr.