back lower muscle pain

Hi everyone!!! I am having a back lower muscle pain that is feeling really tight (I can't bend over down too much because it is not letting me stretch it ) and need to stretch or anything to relieve the tight muscle pain... Anyone have any idea what or how I can stretch? any suggestion? I hope I am explianing it well for anyone who can understand what I am talking about.   The pain started after I was cleaning my place and standing a lot also walking around for 3 hrs or less. maybe that is too much for me? please help me. thanks!