Lead Photo Credit: P. Howe
When a lifter says he can't squat due to pain, it usually indicates that he's squatting incorrectly. A technique called "eccentric isometrics" is the most efficient way to correct squat mechanics, along with reinforcing proper technique.
The idea is simple: perform the eccentric or negative phase of an exercise in a controlled manner, then pause in the stretched or bottom position for a few seconds before completing the actual lifting/concentric phase.
Eccentric Isometrics on Barbell Squats
Simply slowing down the movement pattern, focusing on sensory information from your muscles, and not trying to exceed your body's natural range of motion will offer more benefit than any corrective exercise or soft tissue procedure.
Any squat variation can be used. The focus should be more on how you perform them rather than the variation you choose. If you're having trouble finding a perfect position, decrease the load, slow it down, and try closing your eyes for enhanced proprioception.