Hello and welcome to the forum. Thank you for the question. This often happens because our inner thighs may rub together against the material of our clothing and the skin is more sensitive. If this is the case for you, it's chafing. They do sell anti chafing products that you could use. Even something like gold bond powder would help. https://www.healthline.com/health/inner-thigh-chafing#treatment this article has remedies to look into.