My BP is always a very solid normal, just a bit low, when my SI joints and curling tailbone from the Stenosis goes to the level of being intractable it can go quite high, my GP does not want me in pain, he wants me to take Opioids as a maintence drug, I will not do this. I take them to break pain cycles or if the pain is so great that I think that I want to go to the Hospital, and you can trust me when I tell you that I NEVER want to go there! There is also a pain in the ribs that has been severe, Doc has even had to give me Demerol shots in the Sternum area! WHEW!! He is the only one I would trust to do this. I get so bad I can barely pick up a coffee cup or dinner plate. It does break the cycle, I can get 'crashed' in bed for long periods, the dope does help either break or prevent that.
My DC is also a personal friend, he cannot advise me on meds, but he can walk me to the car and say "Susan, as your friend, I think you should take the pain meds"! In case anyone would be unfamiliar with Chiropractors, they do not like or believe in narcotic use, but he knows it is better than me being in bed for weeks, even months.
As for BP, no worries there, my Doc is most concerned that there is something yet undetected, as good as he is, he insists that I additionally go to a Rheum, and I know that this is the reason. They keep looking for Lupus or MS or something in the neighborhood to show up.
lamb and Rich have given me some good possibilities for the lower back area, there are also disc and facet problems there. I have just started doing my own research into those possibilities.
I additionallly have Secondary Raynaud's Syndrome, and possiby Scleoderma so my hands and wrists can get bad at the slightest exposure to cold, even a cold drink in my hand for a moment can put me into orbit! Those blood vessels constrict, in the Winter my gal has a terrible time drawing blood, has to use a Premie needle! It never seems to drop it too low.
I think I'm rambling now, not sure I answered your question or not, I think Deb gets something like this as well, she left a comment on 'undiagnosed attacks' that kind of touches on all of this.
When the Immune system goes into overdrive, who knows the crazy things it can do to us!?
Hope you are having a very good day!
SK