What Causes Sciatic Pain, Lower Groin Pain And Towards The Waist?

I am 56 and have had scyatic pain and lower groin pain and pain on my left side at my waist in the back. I have all my female parts, (till two days from now) I went to Family Dr with symptoms. Oh yeah I am post menopausal also. He sent me for X rays, and an MRi. I have deteriorating arthritis/ The pain is more intense than childbirth (with no pain meds, I had for deliveries) . I asked him about fibroids because a year earlier while in the hospital with kidney stones, they found a fibroid that measured about a 4cm. could it be growing? he said prob not because I m post menopause and they usually don t grow then. At this time I was into my 3rd month of pain with no help yet. My FP said we can have a CT scan with contrast, which I did, It showed that the fibroid had grown to 5cm. So he sent me to GYN and he gave me several options , and because of other health issues I decided that the first two were to risky and have decided to have the hysterectomy, in a couple days. No one can tell me is the fibroid is causing the severe pain I am having so I have no idea if this is going to help my main concern. *the pain* . All of this brings me to several questions. Is this thing really growing or did someone just miss measure? (I have never been diagnosed wih fibroids before.. If it ( hyste) dosen t work will it cause me any other problems that I don t need. This pain has been at a pain level of 8 to 10 for 6 months now. pain meds aren t really touching it and I ve tried a steriod shot, steriod pack, muscle relaxer and pain pils (norco 7.5) do you have any comments?