Help please

I have this weird feeling around my Opening of my vagina (below the pee hole)

It gives me a burning feeling when touched or when i wipe after i pee - i dont have any reason to have any sexual diseases but i am really worried as it is very uncomfortable to even sit still.

I think this was because i wore New knickers which were a strange fabric and as soon as i took them off the burning began .

If youve ever had this or know what it could be please help me