There have been many great suggestions made in this thread. I too, have back issues(S4,S5 & S5,L1 ruptured discs) and everyday my back reminds me of those problems. That said, cycling has rarely, if ever, bothered my back. I think with proper bike fit, core training, ibuprofen and LOTS of stretching you will be back in the saddle. Good luck and get an MRI.