Hi,
I recently started weight training program, about a week old.I've been practicing martial arts for sometime and have decided to lift weights for some strength and muscle gains along with a need to strengthen my core.
Last evening, I did my round of Squats, Chinups, Overhead press, prone bridges and ended with deadlifts.I warmed up for 5 minutes before I started with my workout.
During the overhead press, I started developing the sore lower back which is natural since I my lower back is weak and this is why I have adopted this program.Now, during the deadlifts I think I had a bad form though I tried not to. I think my spine was a little rounded.I think I also didn't unlock my knees as I came down with the weights.The soreness didn't increase much but I decided to stop after 3X5.
After I was done removing the weights from the rod, I tried to stand up but I felt a sort of a slip in my muscle at the left side of my lower back along with sharp pain in that 3 inch area.This was followed by tingling sensation throughout my left leg( thigh+calf)
I am not sure if I have pulled a muscle or it's a muscle strain or something but it hasn't subsided completely.This morning it seemed a little better but during the day with work, it's back.
I lifted 30KG(instead of 27.5) on the squats and overhead presses and 50KG(instead of 45) on the deadlifts.I know this is not strictly according to the program but I dont have the exact weights for it and I didn't have a problem lifting these weights at all during the 5x5s
The blue square is where I am feeling the pain.

http://img692.imageshack.us/img692/6281/backpain.jpg
The pain is dull but gives me sharp pains if I try to bend down or if I try to twist AND bend down to the right.Could any of you what's really going on?Is the Psoas that is getting affected? The pain is nowhere near my spine.It's just the chunk of mass which is giving me sharp pains but I have a bad feeling about this.The tingling still persists in my leg.
I apologize to be too descriptive and taking your precious time but I would really appreciate some insight on this.

I'm not a physio so I'll avoid giving too much specific advice on the injury but have you tried applying ice to the area? If I were you I'd take a rest until the are feels better, keep allying ice packs and wait a few days to see if the pain subsides. I'm not sure but Iboprofen might help a little by reducing any swelling in the area

Once you're back to lifting again I'd also suggest getting someone to check your form. If you don't know anyone that can do this for you then try and get a video and post it up here for us to look at.
I'd also try and seperate the days you deadlift and squat, they're both pretty intense lifts so you'll probably get the most benefit from having a day or two to rest between performing them. As well as that, you're going to find it harder to maintain corrct form if your legs and back are already a little fatigued from previous work in the same are

Typhon,
I've done a the cold+hot treatment once here in office(no icepacks, but bottles of hot and cold water).I would be doing it more once I reach home.Should I do that or just Ice packs is enough?
Yes, I think I would need to post a video of my form.I thought I had a good form yesterday.I was careful.But today when I was reading up on this injury, I found out my form was not entirely correct.

I usually just use ice to reduce any swelling but a lot of people use heat and ice, I think alternating the temperature is better for pain relief

Posting a video would be ideal but remember what I said about doing squats and deads on the same day, if your legs and back are a little tired it's going to be harder to maintain correct form so splitting them is usually best

I’ve heard that intermittent icing is used because once the ice is removed, fresh –warm- blood floods the area increasing circulation, speeding up the healing process.

That's the theory behind icing the area, but I thing applying heat after ice is to confuse the pain censors feeding back to your brain which eases suffering

The OP sounds like he is doing the modern version of stronglifts 5x5 and either hyper-extending his back or has lower-back rounding issues. Correct form ASAP. Remember RICE (stands for Rest, Ice, Compression and Elevation) for treatment of your injury.

Blackbeard, you are right.I have started the Stronglifts 5x5 program.That said, squats are included in this program for every workout(or rather everyday you chose to workout).I am not blindly following this.Squats really seem to be a very good compound exercise to make the legs, and core stronger.
But what Typhon says is also true.Since I've just started this training, I dont know whether it's a good idea to mix deadlifts and squats on the same day.
I've done the icing and hot water bag process right now.I do have some relief.

But I haven't got the answer to my question yet.Is this something which is quite common for bad form? Based on my description, could you guys figure out what part of my muscle seems to be affected?

I will take a better look at my form for sure.

I used to get pain from time to time in exactly the same area when I didn't pay such close attention to form, it was always milder than you're describing though so although I want to say it's probably a minor strain and rest will cure it, I wouldn't want to promise anything.

And I know this isn't an answer to the injury thing again but I would question the use of a 5x5 strength gaining programme for a newcomer to lifting. A regular 3x10 will allow you to make significant muscular adaptations while keeping the weight low enough to focus primarily on form

Stronglifts 5x5 is a recognised program as is Starting Strength where you do Squats and Deadlifts on the same day. I have done the 2008 version of stronglifts but the principle is the same. In the famous words of Madcow, don't f*** with the program. The 5x5 has worked for many,many people since the 1970s so don't change it, if you are doing it.

1. Learn proper form for Squats and Deadlifts. There are videos on the stronglifts website. Don't add any weight till your form is 100% spot on.
2. If your form is correct and you have no injuries, follow the program religiously, don't try to mess it around. The great gains come from squatting 3x per week.

@Singalong, your problem is not a new one -
Why Your Lower Back Hurts on Squats & How to Fix it

I hurt my back twice doing DLs on the same day as squats, both times it was my fault. i wore myself out with the squat and was too tired to do a strict DL. I dont know if it fits into your program, bu maybe you can choose the one you want to focus on that day, do it heavy, then do the other movement light.

I see no reason why you can't do deadlift and squats on the same day as long as you concentrate on your technique. If you've only been in the gym for a week don't be giving it 100% straight away. Instead keep the weights at a level where you can maintain good form and gradually increase them as long as your form stays good.

I'm no physio either I'm a PT, but I just checked a book to make sure I'm right and I am (well the book thinks so anyway!) Using ice is good for about the first 48 hours, after which it is only good as a pain killer, so after about 72 hours do some gentle stretching. This shouldn't hurt. I'm sure you know the difference between stretching pain and **** me that just feels wrong!!! If it's a little sore after try ice but again this is a pain killer. Also one tip from personal experience - be VERY careful after icing a muscle until it has warmed up again. Making the injury worse is very easy when the muscles are so cold.

From the diagram you sent it looks like you've damaged your Erector Spinae muscles which makes sense given the exercises you were doing. I tore mine many many years ago when young and it give me problems for years after. The solution - I concentrated on my technique instead of the amount of weigh I was lifting and bought myself a foam roller to stretch out the muscles that had been tight for years after the injury. Never had a problem since. Everyone should buy one as they're only about $50 and not only are they good for loosening tight muscles they are sooooo relaxing!

David.