It could be from your clothing rubbing against your skin with the recent walking you have been doing. Does the material on your clothing seem to irriatate that area? The friction combined with sweat is probably not a good combination and may be the cause of your irriatiation. Make sure you wear cotton underwear, as well as cotton clothing that breathes (instead of sweats, maybe wear cotton exercise pants the kind that are made of the thin material that will allow your skin to breath. From the sounds of it, it's probably not a yeast infection or UTI.... I think it's the friction and sweat creating an irritation. You could try using a cream on the irritated area (like vasiline, or if you know of anyone that has a baby use some of the A&D ointment that is used on diaper rashes) I know it sounds strange but it will help it heal and also protect the sore area... A&D ointment (or something similar would probably work a lot better than vaseline... if if you don't have or can't get any of the ointment.... try maybe some talcum powder, or an antiobiotic ointment (Like neosporin). I hope those ideas help you. Good luck.