KNEE PAIN WITH STAIRS....AND SQUATS
It’s likely due to compensated body mechanics from tightness in the low back and/or hips.
To walk stairs with ease (and squat correctly), you have to be able to:
Keep your foot flat with weight through the heel (full ankle motion)
keep your pelvis and spine neutral...feelings ABS and HAMSTRINGS (front to back balance)
Shift your hip back as you reach the other foot down to the next stair so your knee stays above your toes, not beyond them (hip internal rotation/adduction and posterior capsule mobility).
Going up and down stairs is basically a series of single leg mini squats!
Squat to climb stairs and climb stairs to squat!
* Side note: my clients are usually the only ones privileged to see my stick drawings 