If you've been experiencing a pinch in the front of your hips when you squat, you've likely tried dozens of hip flexor stretches to get rid of the irritation and so you can squat more comfortably. You likely haven't had much success with those stretches either.
The reason hip flexor stretches don't help in this case, is because the pinch is occurring when the hip flexor is in its most shortened position, indicating muscle length is not a issue here. So what is the causing the pinching? Usually either squat stance or core stability and hip flexor strength.
Hip anatomy varies wildly person to person, yet for some reason we are all taught to squat in the same way. We were all told to point our toes forward with our feet hip width apart, but there are very few people who can squat comfortably in that position.
To find the best squat stance for you, move your feet closer together and farther apart and try pointing your toes out at various different angles to see where you can squat the deepest most comfortably. As long as your knees aren't caving in and still track over your toes, any stance width and toe out should be fine.
Core Stability and Hip Flexor Strength
If changing your squat stance didn't help, there may be some strength asymmetries to adjust. Most barbell sports are posterior chain dominant, meaning the anterior core and hip flexor require intentional work.
Set up a small object at your ankles. Without leaning back on your arms, lift each foot up and over the object. The taller the object, the more difficult it will be.
Kettlebell Hip Flexion:
Grab a pull up bar and loop a kettlebell on your foot. Pull your knee up to your chest, keeping your abs squeezed tight. If your grip strength is lacking, perform the hip flexion while standing on a box so the kettlebell can still hang.