What Causes Swelling At The Back Of The Head?

I do have swelling on the back of my head and i have been using ointments to treat but it cannot go away completely,this had been the case for the last 7 years and i kindly need your help.Two i have been having dundrufts if so on my head and it makes my head looks white how can i get it back to its original colour am a black african man.