I Went To The Doctor 6 Months Ago For Lower

I went to the doctor 6 months ago for lower back pain starting in my lower back and shooting into my butt and down my right leg. She told me it was a pinched siatc nerve but gave me meds and said it would come and go. Now I still am haveing the pain but I also developed a a golf ball sized lump on my right side lower back its painful and verry itchy and red.. My back and hip are also verry swollen do u have any idea what this could be?