Hello there is nothing to worry Loss of normal lumbar lordosis means that the spine has different curves at different levels of the spine so the normal curvature at you lordosis thats your lower back has reduce would advise physiotherapy which can help you regain the correct postural alignment . Muscles spasm is the muscles have got tight you may apply heat pack for 20 mins twice is a day Would advise you to visit a physiotherapist who can assess the cause for this and treat you and show you exercises accordingly Its difficult to advise more as the cause of this happening and duration of your back pain is not mentioned .