I am not sure how these are caused but I would think you would need to figure out what it is that caused it and try to avoid that exercise. I had a pinched nerve in my right hip. I had no idea what it was but I kept going with my biking and my leg workouts. One day I decided to change my seat on the bike and it seemed to fix everything, took a while till there was no pain but it has never come back.

As for back stuff I would definitely get a belt. If you are doing work around the house and such go for one of these http://images.allegrocentral.com/2B...ing-Belt-500307-PRODUCT-MEDIUM_IMAGE.jpg and if you are weight lifting then go with one of these http://www.physiquebodywareusa.com/Images/Large_Images/Weight%20Belt%20Lg.jpg.

I would also say, don't stop doing back stuff. I would go for body weight exercises, physio will give you a bunch of stuff you can do. One I can think of is do chest raises, you can either raise up all your limps or do alternating, left arm up with right leg then switch.