I had hip replacement surgery in May.  Ever since then I have had a lump insie my left buttocks.  The same side as my hip replacement.  I told the Dr. and he said it will go away, but it is now November and its still there.  It hurts to sit down because of the golf ball.  I can't seem to get answers.  What is this and what kind of Dr. do I see to find answers.  Also sometimes the lump moves to the side of my hip replacement.  I need help.