What Causes Spot Of Soreness In A Specific Area On The Body?

Ten years ago I started having soreness to the touch of my skin on my leg. It was a small area on the leg and it would last for two or three days and go away. Every time that it happened it would always be in that same spot. After about two years it started moving to different areas of my body and it s always a small area. I ve had it on my leg, arm, neck, head, face and vagina. Like I said it s always a small area and it will come back every two to three months. Just touching the skin hurts and if I m up and about it can be bothersome. Also it s not on my leg, arm, neck, face or vagina at the same time only one of them.