Why does my skin keep chafing?

It certainly does sound like this chafing on your thighs might be from rubbing against clothing as you are walking around. This problem is common, and it is often worse in cold weather, which tends to dry out and irritate the skin even more. There are some simple things that generally help in cases like this. The first is to make sure you are not wearing tight clothing, as this will make the chafing worse. In addition to this, a good skin moisturizer is in order. You shouldn't use a 'cream' as these are too water soluble and do not provide long lasting skin protection. Rather you should use a thick ointment, something 'greasy' like a petroleum - based product, which will stay on the skin longer and provide better protection. Also you should avoid excessive showering or hot water, as these will dry out the skin and make the chafing worse. In any case, you should definitely see your primary care doctor (or a dermatologist) for a diagnosis. Sometimes persistent dry skin or chafing is a sign of an underlying skin problem, such as eczema, and it requires additional prescription medications to clear up completely.