My Barbell Squatting form has changed significantly since I added some muscle and about 50 pounds on my squat. When squatting under basically any load, but more so with heavier weight, I've now noticed that my right leg will slightly flare out. It appears that my hips are slightly twisting. As a result of this, for about 6 weeks now, my left calf has grown a bit larger than my right one. I have stepped up efforts to improve flexibility by doing more intense quad, ham and calf stretches as well as squatting with no weight at home. I have since switched to the smith machine to retrain my form, while not having to worry about balancing the bar. The stretching and switch of squatting exercise has begun to show improvement. Are there any hip flexor or stretching exercises that someone is aware of to completely correct this flaw?