well i['m high bar squatting since i lack mass for low bar and also its not comfortable, shoulders quite stiff.
high abr yes pain ill vanish. if ur already doign upper body shoulder work it'd help especially when the time under tension is long for certain sets and reps scheme .
tbh my upper back feels tired more and sometimeeeees a little numb at my rear delts if the bar is on my back too long(normally when i push my 6/7RM to 8reps) rather than "pain". however i did 5rm yesterday, and got stuck for a sec on the way up in squats which should've gone smoothly without being stuck in any point of the squat. that really prolonged the time of tension, especially with the amount of weight. now i'm feeling that bone soreness when i first high bar squatted, except it's not the whole line on my back but just around the rear delts. gotta focus on tensing my back next time though.
but to cut the crap, you should be fine dont worry:) 2-3sessions into it and u should be fine