What can you use for painful chafing along inner thighs and testicles?

Fungal infection: Painful chafing along inner thighs and scrotum sounds like a fungal infection. Are testes themselves painful? If yes, need to see urologist. If not, likely fungal infection of skin; keeping the area dry and clean will help to rid this issue. If it is not improved with using Miconazole nitrate 2% powder (available over the counter), you should see dermatologist or urologist.