Hi I Fell Almost 3 Weeks Ago & Had Massive

Hi I fell almost 3 weeks ago & had massive bruising on my right buttock also a lump appeared & is very hard & painful the bruising is almost gone but the pain & stinginess is stil very painful iv been putting on deep heat & taking pain killers wondering what the lump could be? & how should I treat it im still at work as a school cleaner & the lump gets sorer & really hard & stingy when I'm moving about but settles when resting can u advise me what to do plse thankyou