You have given no exercises other than the full squat and your explanations hardly elude to strictly hip issues and in some ways indicate there is much more to address (which is likely the case).
i would warm up - a good warm up, perhaps 30min at least 1st - jog, mobility work, med ball throws, strides etc etc.
Then get somebody to help you out with the stretching. a good PNF workout with static where needed when they are too hard to PNF.
Perhaps your doing Foam roller wrong as well? It might be worth your while to seek out a physio or such to show you?
how about calcium supp? magnesium supps? Bromelain? all good for relieving stress out of the muscle.
obviously you cannot read…
i just went back, and counted 10 - in bullet format - and as i said then, a small list - indicating there are more, here is just a small sample.