lump right behind tooth on roof of mouth

Hi, I have had a small hard lump on the roof of my mouth, right behind my two front teeth. I never really notice it until sometimes it will get sore as if its cut or it has been rubbed against something and is irritated. I was wondering if this is normal or is this dangerous? I had a tooth removed from my gum (a very unusual case) where the tooth was growing on top of my adult tooth and pushing out from the gum and im not sure if this could have caused the lump. many thanks in advance.