Hi this may be a sign of blood clots or phlebitis, which can become very serious.
It may also be nothing more that a Charley horse due to the way your leg was placed while you were sleeping or a muscle spasm due to a number of different causes - often these occur at sleep transition and can be very, very painful and feel much different than when they occur while awake.
Please answer a few questions!
Do your feet and ankles swell? Can you see your blood vessels in your legs, feet, or ankles? Do you have pain in your toes feet, ankles, or lower leg? Can you feel the pulses in your leg?
If you answer yes to any of these, then you need to make an appointment with your physician and go in for an exam and some test.
Here are a couple of websites that may give you more information:
http://www.nlm.nih.gov/medlineplus/ency/article/002066.htm
http://veincenter.com/phlebitis.html
I hope my information was helpful for you, please note that this is not intended as and does not substitute for medical advice and/or diagnosis. Only your physician can provide that for you, so please see your Doctor, get examined and make sure you follow up as prescribed.
Please click the green "accept" button. Bonuses and Feedback are greatly appreciated! If you have any questions, please do not hesitate to ask. Thank you and good luck. Rick
