Why do my leg muscle jump (flick), is it a shortage of a vitamin?

Likely not: It would be helpful if you give more information about it e.g. how long has it been present and how is your general health. There has to be a reason for a patient to become deficient in essential nutrients.

More likely minerals: This is more likely a deficiency of minerals, particularly magnesium(which is very common), but could also be do to calcium deficiency (also common) or potassium deficiency (less common).Sometimes low B vitamins,esp. B6 or B12 may cause this too. For food sources of magnesium see http://whfoods.com/genpage.php?tname=nutrient&dbid=75 You can take magnesium supplements and also try a good multivit.