This sounds like the same sort of pain I used to get (before I was pregnant) which was compartment syndrome.
"Compartment syndrome is a painful condition that results when pressure within the muscles builds to dangerous levels. This prevents nourishment from reaching nerve and muscle cells."
I got it as a result of high intensity sport but it can also come about in an acute sense from various causes, one of which (interestingly) is
"Blockage of circulation, such as from pressure over a blood vessel for too long while asleep"
It is worse than shin splints (which can also be very painful too).
Might be worth checking out online for more information or speaking to doctor about it, perhaps? Hope it improves.