Hi There. I Have A Lump A Little Bit Bigger

Hi there.

I have a lump a little bit bigger than a pea on my bum crack and has been there for a while I am scared to go to the doctors or hospital just incase they tell me it's something serious and will have to operate it is under the skin and when I feel it it moves and it's sore sometimes,it feels hard as if there is nothing inside it, does anyone know what it can be ?

Thanks Brandon.