You will need to determine the cause. I occasionally have problems and sometimes it is just emotional pain, other times it is that one hip is riding higher than the other so my psoas is very angry and sometimes it's a combination. You can be very fit and still have problems! You will have to find a strategy that works for you.
Pilates helped me. My posterior chain was weak. I use short Pilates for runners workouts 10-20min. I really don't like Pilates, it makes me think too much...squeeze this, hold that , don't forget to point.....It's maddening!!!
I got the help I need for my back and neck issue by finding a chiropractor who specializes in corrective care. Only one who takes xrays and shares her/his plan with you. My Dr and physical therapist wanted me to see a surgeon. I decided to see if a Chiro could help and it has changed my life.
As for Cathe workouts I modify core work (Planks are a better choice for me) and keep my step to no more than 1 set of risers for cardio. A higher step (And many high impact moves) seriously affect my back. Finally, I have found doing a yoga workout once or twice a week really helps.
I hope your back gets better soon! I know how horrible it can be.
I always love steps dvds and all the jumping but 4 years to now I been able to do it, and I have to sell a lot of my Cathe dvds, I start with leg pain and sharp pain in my lower back, I do have a sciatica and spinal stenosis, L4,L5 dislocated, I been have my injecctions every 3 to 6 months for pain, I always lisen my body, now I'm more focus in lifting more and less cardio. Check with the doctor and ask for MRI, don't wait for too long.
Hope you feel better.