I Have A Hard Skin Lump On My Right Buttock...it

I have a hard skin lump on my right buttock...it is just below my waist...when i touch it...it is paining little...what shud i do now...shud i worry a lot...m also having lipomas skin bumps all over body...bt this buttock skin bump is different than lipomas bumps...lipomas bumps are not painful..but this buttock bump is paining...