Back MRIs are weird. You'll get people with herniated discs with no symptoms and people with clean MRIs in pain. And of course, people experiencing pain that the MRI finds the cause of. It's also possible to have two sources of pain. It could be DOMS plus a herniated disc.
I'm mostly pointing this out because "back pain" has scary connotations, any sort of pain gets them worried, even if it's just DOMS.
It’s a inflamed joint creating sciatic nerve ‘irritation’ and Some disc compression.