My Nose Is Very Sore On The Side...the Surface Of

My nose is very sore on the side...the surface of the skin is red and a bit swollen. I have not been hit with anything and i don't see anything inside that may be causing this..the soreness actually started on the other side of my nose a couple days ago and has moved to the opposite side! This started happening several months ago and has done the same thing before..the pain travels from one side to the other!! Then it disappears all together like it never happened at all..why is this happening?