When will I be able to stand up straight? I had tummy tuck and breast lift July 3.

You may find yourself hunched over for a few days post op; this can be attributed to a combination of repair and incision.  The muscles have been irritated to a certain extent by plication and the surgery itself.  I only tighten the abdominal wall to return it to an anatomic norm rather than tighten it as much as possible. This produces a functional result without producing prolonged discomfort.  The abdominal wall may need several months to get accustomed to the changes.  You should be walking normally by week 3 but perhaps at a slower pace.  
Kenneth Hughes, MD, ABPS Board Certified Plastic Surgeon
Los Angeles, CA

You should notice gradual improvement in being able to stand fully straight.  The amount of time it will take will depend on the extent of the surgery done.  In the meantime you can have a partner massage your lower back with a tennis ball and use warm compresses to help with sore back muscles.