i had pain in the lower back initially for which i took pain killers.the pain has reduced but i still have stifness and at times slight pain comes back in 1 0r 2 days.the pain that now comes is at times in the lower back and at times it is in the middle of the back. i do slightwalking and other regular activities but then i don't get the pain . it just comes anytime and its more of a stifness feeling rather than a pain. so i wanted to know what can be the cause and what treatment should be done for this.it's almost been 20 days that i'm having this problem.