creeping numbness

I wonder if I could have this?  I have a mystery disease that started with rib pain, added back pain, and got to the point where I could not stand or sit.  Then my legs started buckling and tingling, until I have what feels like cardboard toes, and numbness that has crept up my legs to my ribs.  Prednazone helped the rib pain a little, but ibuprofen has helped the best.  I now walk very unsteadily with a cane, and cannot trust myself to go far.  I try to exercise my legs every day, but along with many other symptoms, I am very weak, in a lot of constant pain, and my doctors do not know what's going on.  Susan