It's hard to remember to do your exercises and stretches - but with google calendar, you can get reminder emails, and get the satisfaction of deleting those messages after you do each set of exercises. This is particularly helpful if you are doing an every-other-day exercise. By having the reminders sent to your inbox, you ensure that your regular everyday practice of checking your email is all you need to get reminded.
One of the tricks with lower back exercise (and stretches) is to start at a very moderate level, and then ever so slowly increase the intensity and rep count. This ensures that you don't injure yourself. If you have trouble remembering to do your exercises, however, this slow ramp up process will never progress far enough to actually gain muscle strength and greater mobility. This is one big reason why something like google calendar's reminders are so helpful.
To set up reminder emails, add an event to your calendar, and then click on "edit event details". Set "Repeats" to weekly, and then check off the days you want. Then click on "Reminder" (under options) and set it to email you 10 minutes before (or whatever). Try to add the event to our calendar around the time of day when you could actually do the exercise (the assumption being that you check your email pretty often).