Lower back hurts. Permenant problem or short term?

[mused01]

My lower back started to hurt yesterday when I was buying a TV stand for my new 46" 1080P LCD (not a thin veiled brag). It aches when I stand up but it's not that noticable. However, when I bend down, I can definately feel a midly sharp pain. There could be 3 reasons for this:

1. Lifting heavy objects. I've been working out recently nd I guess that tv stand finally broke the camel's back.

2. Cheap IKEA mattress. It's total cost came around $300.

3. If anyone has built an IKEA bed, they should be familiar with the seemingly useless metal wires at the bottom of the bedframe. I did not put this as I thought it was a waste of time. Maybe I should? Honestly, I can't see the difference those wires would make. Although this and #2 can be discounted because my roommate has the same mattress and we also didn't put the bottom wires at the bottom and he has no problems.

Anyways, the pain has been there for about 2 days and counting. Should I be worried? It's nothing big, I can still do most activities (although I have laid off working out). I really hope it's not permanent.