I woke up with a pain in the front of my leg in the shin area that caused my foot to angle of. what caused this?

Spasm: It is muscle cramp . Hydrate yourself well. Eat banana and drink orange juice. If you are taking water pill ask you doctor for a potassium supplement. Apply heat. see your local doctor

Shin Splints.: If this was the first and only time you ever experienced this leg pain, then it could simply be that you slept with your foot, ankle or leg in a strange and stressing position. Unless you have caused a more serious injury, some heat and rest should make the leg feel better. Of course, if it returns or gets worst, then it's to the doctor you go.