If it is your a
dductor magnus, I doubt you have a squatting problem. The clue being that you went hiking, then you squatted, then you had a problem. It doesn't sound like you had previous problems just squatting. Squatting might be the straw the camels back, but hiking was the more likely the initial overload.
Shitty stick figure time.
Attachment 47471
If you look up hip abduction and adduction, you get some useless picture like 1) where it shows someone doing scissors kicks.
What your hip abductors and adductors do in their primary function is shift your hips left and right like 2). The do this by you aBductors pulling the outside of your knee up towards the hip and the aDductors work by pulling the inside of your knee towards you taint like 3). If you have a hip shift like 4) that could be a joint mobility issue or an imbalance in the medial glutes. Muscle can pull (contract) and resist pulling (elongation), they never push. As you lower yourself in the squat your aBductors, mainly the medial glutes, need to resist elongation at the same rate, otherwise one side collapses and the aDductor has to pull to shift your hips back under center. (If you have the knee dip/knee valgus/stanky legs when you squat that's you aDductors doing on the stability work on the hips with no help from the glutes. They should be about equally sore.)
For you adductor to hurt from squatting, it most likely had to do with it pulling in place of a weak glute. If you didn't have problems in the past, I don't think you need to worry about in the future. Let it heal and don't squat after hiking.
Look at 5), keep this in mind about hiking. If you're on uneven ground and you don't want you hips to shift to the left, because you head would go to the right, you'd fall to your right and look like a fucking idiot. Muscles can only pull or resist pulling with the foot planted on the ground. Your right adductors do all the work pulling. If you out hiking, your adductors will do a lot of work on uneven terrain.