You should never hurt yourself lifting. Your lower back should never feel pain. Tweaks, aches, pains etc. from movement are just not acceptable in my books!
Why do I get people coming to me every week with injuries from doing daily tasks (picking things up, falling over, losing balance, carrying etc)?
If you don't train movement patterns and teach different muscles to fire, and fire together, your body loses the ability to coordinate effective movement in every day life.
– Many people have extremely weak glutes and lats (back postural muscles). If you sit in a desk all day, this is you. They simply don't use them in the gym, and therefore over time they get quite lazy. Well what happens? You go to pick something up off the ground, and these big muscles (that are now too lazy to do their job) don't fire, and you get compensation from other areas of your body. For example, you might try to pick up a log from the ground using only your arm, as opposed to efficiently using your entire body to lift it up.
I know that any person who wants to keep their body feeling and working well long term needs to get a handle on how to pick things up off the ground properly.
One leg deadlifts (using a weight), suitcase deadlifts, regular deadlifts, squats, are all important movements to perfect in the gym if you want great use of your body long term.
If you can honestly say "I don't quite know how I would properly pick a suitcase up off the ground", I suggest you e-mail me and we can get you set up with a session. In the meantime, watch my brief video where I talk a bit more about lifting: http://youtu.be/nbt9MuKgcjA
Stay injury free, please!