Cnd timing chains be changed without pulling motor

No, you can't change the chains without engine overhaul per the workshop manual. I wouldn't jump to the conclusion that timing chains need to be replaced. There are possible causes -- with variable valve timing mechanism for example - that could be at fault and be repaired. I'd strongly suggest seeking professional, experienced guidance on this. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops