Squatting and Side of Leg Discomfort/Pain

Hi, i have a problem with my posterior leg muscle ONLY when do weighted squats.
I am new in barbell squats but not At All in bodyweight variations (pistols, bulgarian split ect.) and read pretty much about form and technique of squats.

First time i do weighted squats in summer i feel a tightness around my hips and after 2nd or 3rd series i feel discomfort in my right leg OUTER hamstrings muscles… Few minutes After that i do Hamstrings curls and feel NO pain at all.

In the meantime i improve my mobility in lower body and when i start doing weighted squats again last week, in 3rd series i feel SAME discomfort as then but now in BOTH legs, and it was really light weight -40kg and i was able to lift that weight for 15-20 reps.

I’m not sure why this happens, and which muscle can be but i know that it’s on the SIDE of my leg.
That was just two times in my life when i feel that pain…

So what you recommend, what to do? :slight_smile:

Hey folks, in the meantime i discover that my problem is adductor magnus. It’s happend with weighted squats and also AFTER dumbbell side lunges with light weight. Do you have any recommendation for this, it’s feelt like that muscle can’t resist any weight and always end up STRAINED.