What Causes Sharp Pain In Legs, Feet And Spine?

I'm 20 years old. I had cancer when I was younger, but I've been healthy since until just recently. I keep having sharp pain inside my bones in my legs, feet, and spine. In my arms, it's a searing and tingling sensation like I'm constantly hitting my funny bone. My right hand gets very weak. The weakness doesn't last as long as the sensation, but all these symptoms are becoming frequent. I'm exremely fatigued also. I went to the ER and they completely disregarded everything I said. I don't have a doctor I can go to at the moment. Any information would be greatly appreciated.