there’s some really basic things you can do to build core strength without hurting yourself more… it’s hard to explain without showing you… it also depends what kind of back pain it is… try tightening your stomach muscles and hold it for a count of ten, then let it out. do ten of those in a row, three times a day. it can also help to lay on a yoga mat with your knees bent, tilt your pelvis up and tighten your core, then lift each leg a couple inches off the ground, alternating one at a time keeping the knees bent. try doing ten of those a couple times a day to start. a lot of these kinds of things feel really simple ifyou’re used to a “workout” but if you focus on isolating movements and breathing while you do it, you should start to feel some effects… i am not a doctor or yoga teacher, i’ve just dealt with a lot of back pain myself. good luck.