Thighs Rubbing Together But Im Not Overweight/Obese?

Im 5,5 and weigh 113lbs. I have no clue if its just me but I think my thighs look huge. They rub together. It doesn't hurt or anything but I just noticed it a week ago. When I stand up, the only part that rubs is the way upper part of the thigh. Im skinny and when I wear pants they don't rub together. Is it just when it gets hot that thighs expand? A month ago I was at the YMCA and I looked down and noticed my thighs look huge. I was cold... not hot because I just got out of the water.