I too thought same going to shorter paddle.
learn to hinge at the hips. lock the core, chest out, abs in, strong.
check this guy out, i cannot recommend more for posture, strength, stretching, flexibility. with better posture and a correctly aligned spine better blood flow and less chance of tearing muscles.
www.foundationtraining.com/get into a good chiro
buy a roller
mix with some stretches such as surfstretch (FB & youtube) recommends and you will benefit.
Another thing i have found is harder days to get onto waves the old technique goes a bit out the window.
you are paddling like hell up the nose of the board come on we are on we are on then twerk, muscles start twinging.