Wow, sorry to hear about your back, Ady - I've got scoliosis myself, so I know back-related health problems are no picnic, and that seems doubly so in your case. Here's hoping you feel better soon!
And if you need to take time off of ESB:R for it, I don't think any one of us (besides Sevb32, perhaps) will fault you for it. Your health is far more important than Star Wars.