If you have back problems, yes, you will definitely need a nice--to-push stroller that is, ideally, on the lighter side. It should, also, have a nice suspension if you need it for uneven roads, which, from my point of view, puts the Inglesina Electa aside - it does have suspension, but not too soft, and you'd feel the shaking a bit too much.
moving on, the choice between the Harvey3 and the Uno 3 Plus is clear to me - I personally would go with the Harvey. It pushes very very nicely, and, compared to the Tutis, has a much better seat unit and overall higher quality. I heard too many complaints about the frame or the seat of the Tutis prams that needed replacement (which was given, just saying), and Easywalkers have lifetime guarantees and not too many complaints about the quality. They also push nicely with the seat in the parent-facing mode, which is not true for all parents with the Uno, or at least that is my experience - and everybody has a different one.
I hope I helped you, I only provide my personal opinion, of course, and the best is always to try in person (with a loaded, not empty stroller), so that you know what exactly works for you ^_^