Is this brought on with exercise or always like this? If it is always like this even without exercise and it was compartment syndrome this would be acute and not chronic... you'd need to get to the ER otherwise you'd be losing the leg.
https://orthoinfo.aaos.org/en/diseas...ment-syndrome/
If it is exercise induced this can also be a cause of a nerve issue but it isn't usually a medical emergency.
If you already know this then I apologise in advanced as this will come across as patronising if you already know it. Your muscle is in a casing called a fascia, when you exercise the muscle expands due to the increase of oxygen,blood and pressure going into the leg. If your muscle is too big for your fascia it will attempt to expand but this will be restricted by the fascia which leads to a build up of oxygen, blood and excess pressure which causes the crushing sensation and deadness. This obviously subsides in exertional compartment syndrome when you stop exercising.
but with an acute case you need surgery to correct the injury which is causing it.