What Are The Symptoms Of Cell Hypoxia?

What exactly are the symptoms of Cell Hypoxia? Sometimes I get cramps in my lower legs, and I guess they're the muscles contracting and they always hurt really bad so I just to stay still and try to breath normally. It started with the soles of my feet though. So I heard about Cellular Hypoxia and I was wondering if I had it or if I should just drink more orange juice.