deadlifts, hurt back!

about 2 months ago i started doing deadlifts. i could handle alot of weight doing it but decided to take it slow because of injury. last saturday i deadlifted 300 pounds and my back just carked it. i didnt warm up or stretch enough. sharp pains in my back still havnt gone away, but the pain is getting weaker everyday that i wake up. i put deep heat on and painkillers but it still hurts, what should i do?

Stay off it.  Keep up your current approach to therapy.
 
That's good that it's going away -you likely just strained one of the dozens of spinal erectors.  If it was a herniated disc or worse, you'd be in constant pain.
 
Personally, my most common recurring back irritation are rhomboid strains.  They usually occur because of an imbalance in lifting technique; one side fires stronger than the other, or an opposing muscle doesn't activate to counter the force.  It only takes a split second of lax muscle coordination.  That puts an assymmetric load on the joint, and when the weaker muscle finally does kick-in, it over-corrects and cramps up.
 
You may have to drop the weight back by as much as a third and spend some time getting good and familiar with the sensation of deadly-strict form again.  Obscene deadlift poundages aren't terribly impressive if you can only brag about them from a hospital bed

Yes, that's me in my avatar, and NO, I don't look like that today. That was taken back in Jan '07, and I lost most of that progress when I slacked off last year. I'm on my way back, tho, and I'm using that photo for inspiration.

always a good idea to warm up first before you tackle the big weights.

You said you tried heat. Try icing your back and take tylenol. Your back is probably strained and also stiff. You probably need to stretch it out, and before you try to dead again, hit the hyper-extension bench and just do a few raises and see how your lower back feels

Age: 24
Height: 6'0"
Started at: 120lbs, 10%bf
Current: 180lbs, 10%bf
Next Goal: 185lbs, 8-10%bf

Mirrors don't measure progress, they just show how much more there is left to do.

Sports injury first-aid
 
psst ... ALWAYS warm up!

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"Push your limits — define aggressive goals"
_________.P R O G R E S S___P I C S

If you did what I did to my back you'll need a chiropractor. But I hurt it in august and I'm still in pain so I hope it's not that bad for you!

5'6" 125/ Bench: 115 / Front squat: 90 / Deadlift: 205 / Pullups: 10