Why do my lower back hurts really bad when i bend over too scrub the toilet or bend over to clean the tub?

Back pain: Back pain is a function of many things , aging, genetics, repetitive activities such as bending to clean things at ground level, prolonged positions such as staying crouched or stooped while working in a bent position . All the above strains the supporting structures of the spine such as the muscles , tendons, ligaments . Try limiting certain positions as well as the length of time in them