What to do about bad posture?

[Forever the '80's.]

Due to many years of lifting in my job, my back has taken a bad turn, and my posture is not good like it used to be. It actually hurts when I try and stand straight. I am making a doctors appt. soon, but thought I'd ask on here what some of you have done or do with similar problems with your back?

Is there any exercises or something that can help with this? Thanks a lot.