Similar here, first after a hockey game (ist in 15 years) at 35. Come and gone since then, until a proper “cannot move, get me diazapam” day a year ago. Physio (back specialist, recommended by my friend, his colleague) reckoned it was down to me not using my back as it should – moving stiffly, being scared of being too mobile in case it instigated another incident.
His advice was to relax and use my back more – seems to have worked.
55, runner, cyclist, office and shop (ie standing) worker mostly.