I feel ankle pain after wakeup and a long seating rest, unable to walk for sometime, why?

Soft tissue: Structures contract while at rest and it is their pull that causes the pain you are feeling....See foot/ ankle doc for clinical exam and treatment proposal.

Nerve compression?: If pain or tingling develops after being in a particular position for a period of time, it may relate to pressure on the nerve. If your discomfort is not prevented by changing the positions that are associated with your pain, you should see a health professional for more complete evaluation.

Ankle injury?: Have you sprained or otherwise injured your ankle? You need to have this evaluated by a physician who can personally examine you. Wishing you health and speedy recovery.