Rash on testicles and between thigh and testicles. no sexual activity. what treatment options are available/what could it be? began running recently.

Jock itch: If running and sweating more, the rash is most likely jock itch, which is a fungal infection, can be treated with over the counter topical medication. All rashes should be looked at by a professional for confirmation.

Chafing: This problem certainly sounds like it could be chafing/irritation related to the running. However, another possibility would be a fungal infection triggered by increased warmth and sweating that could accompany the running. Could carefully try Hydrocortisone cream for chafing, but it could make a fungal infection worse. There are several non-prescription anti-fungal creams available.