Cant squat with flat feet.as soon as my lower leg gets about 30 degrees away from vertical, the heels come up. i've been that way all my life.

Ankle restriction: Your feet come off the ground because your ankles are unable to flex (dorsiflex) enough forcing heels to come off ground. This is either due to a tightness in the back of your ankle ( tight achilles tendon most common) or scar tissue. This can also occur because you have scar tissue or bone jamming in the front of your ankle. Nedd to be examined + X-ray possible MRI

Tight Achilles: Your Achilles tendon is tight, which is a combination of genetics and improper stretching. It is very important to stretch properly before and after exercise. I recommend you see a podiatrist for evaluation and treatment.