I have a sharp pain in my left thigh. comes back every other second. it's been going on for the past couple hours. i did sleep weird, but still idk.

Give it time: Likely a non-serious pain from a muscular spasm or an irritated nerve from the sleeping. Further symptom progression such as redness or swelling may warrant an urgent evaluation by a doctor. However this is likely to go away on its own within the hour.

Not likely serious: A sharp pain every other second is not the typical symptom for a significant illness . There is a common nerve condition of the thigh but it doesn't usually cause this type of pain. Rather it causes numbness and tingling or a burning pain. I suspect your pain is unlikely to be a sign of a significant problem and will shortly go away. Of course it it does persist you will need to see your physician

See MD: See your MD for a physical exam to determine the cause of your pain. Your physician needs a careful history including any trauma, medical conditions and to examine you to determine the problem. Good luck.