Last year I started Nate Green's Built For Show program and had made considerable gains in many areas of lifting. My squat went from just below body weight (165 at the time) to 230 within a 3 month period (give or take a week or two in any direction), as well as my deadlift making leaps and bounds, etc.
Well back in November I ran the Tri-State Tough Mudder in NJ and around mile 10 of 12 I had a sharp pain in my right hip. I finished and all that good stuff, but afterwords it got worse. My guess is that my sciatic nerve swelled up and it only got worse once I stopped moving around. I had to make the 10 hour ride home in the back seat of my team's vehicle with my leg propped up facing the windows. After a few days the pain went away. I didn't notice it again until the next time I worked my legs with squats. It didn't really hurt so much as feel unhealthily tight.
Along with feeling tight, I've noticed that my form has gone to complete shit as well. I can squat half way decent with just the bar, but as soon as I add weight my knees cave in and I get a ton of pelvic tilt. My abductors and practically every other muscle in the glute/hip region feel like they're tight enough to cause an injury if I don't get things fixed.
What are some thoughts and opinions on this matter? What I've been doing (per the advice of the former BB'er that runs the gym I go to) is ditching the bar squats and doing sumo squats with a kettlebell between my legs. It's helping with the knee caving issue but my nether regions still feel tight as hell.