Best way to look after back i'm doing 3 days a week weights and one day core i have massage each week to hard ones ok massages won't damage disc?

Probably not: It would take brutally aggressive massage to injury a spinal discs. The discs are in between the bones in your spine. And there is no access to them from the back, because they are protected by the posterior spine bone structure. That said, massage can make you sore if it's aggressive. You should seehow it goes and whether you're overall feeling better with the massage over time.