Pain in my squat

[CSNYC]

I've been training for more than 20 years. I used to squat 315 3 or 4 times at 155 (I was skinny as hell then), and I loved squatting. Then about three years ago I was warming up with 185, and something went terribly wrong on my first rep. Coming up from the bottom of the hole I felt a shock through my back that was excruciating and I immediately stopped. I saw stars, then somehow got out of the gym and went home.

I've never been able to squat effectively since then. My back just feels weak even when I have 135 on the bar. My hips are stiff, and I feel a sciatica sort of pain running down my left leg. I don't know if that day caused it or if something else evolved over time, but the weakness, stiffness, and pain are real. I actually sweat profusely when I furnace the bar bar and feel the full weight on my back. I had x rays and they didn't show anything. I've tried squatting over and over again and it just doesn't work. It never feels any different.

Please give me advice on what I should do. If I need to see a certain kind of doc I will do that. Or, if there is some exercise I should do I'll try it. All of my upper body lifts are solid. I've been resorting to the leg press machines to compensate and I can do a significant amount of weight there. Also, I notice no pain in my back when I do them. Does that tell you anything? I love squats and would so like to get back to doing them.
Thanks,
C man

[Mark Rippetoe]

You need a diagnosis, which we cannot give you here.

[CSNYC]

Thanks, Rip. I didn't mean to put anyone in that kind of position. I meant to ask
1) For a suggestion as to what kind of doctor I might consult with and
2) If anyone living in NYC knows of a doctor here who deals with issues like this that they could recommend