 [ Symptoms ] i am having a sharp spasm like pain in the back of my left leg about 5 inches above the knee should i be concerned [ Disease ] probably not the area you are describing the back of the thigh consists of a trio of muscles we call the hamstring  what you are describing sounds like a common spasm or cramp of the hamstring this can happen for various reasons    or no reason at all the hamstring would be an uncommon place for a deep vein thrombosis to arise particularly in the absence of any other contributing factors such as recent joint replacement surgery muscle cramps in general can signal dehydration or even a mild potassium deficiency so you could try drinking more water or eating a banana assuming your not allergic to see if that helps the situation if the cramping does not clear up on its own you certainly can put a call in to your primary health care provider for an appointment to have this evaluated hope this helps