My first time on this forum, so I may say things that were already said elsewhere...
My first impression about your dream is that it is a warning or even a sign that something is not right with your leg. However, here are my observations regarding dreams, and if you undestand these, you'll be able to better understand your dream:
1. It is important to see if you had any strong emotions in your dream. Eg: you were petrified of those snakes - that would take away from importance of the dream and point to an unexpressed fear you had while awake (like after you experienced or saw something). If you were observing what was happening to you, with no emotions, the dream should not be ignored; if otoh, you were scared, the dream is not that important.
2. What's equally important is - what associations do those simbols have for YOU. For instance, I have met a lot of people, myself included, for whom water = sickness. The more dirty and/or more dangerous the water, the worse the sickness. Also, the more immersed we are in it, the more immersed we are in the sickness.
3. Is what happened in the dream in any way connected to reality? In this case, maybe you really had a strong pain in your leg while asleep, and that pain woke you up? Maybe you had a muscle spasm, or there is an injury, or something else? "Bolt of lightning" points to electricity which is what causes a spasm, so maybe that was that?