See a doctor! Now!
I'm concerned about your legs giving out on you! this symptom, combined with the lumps near your spine, could be due to a tumor pressing on your spinal cord.
It's important that you go to a doctor or an er immediately! don't let fear prevent you from going, as they can help figure out what is wrong. If it's something involving your spinal cord, waiting might mean being paralyzed! go now!