Do you feel frequent numbness and tingling sensations in your arm, hand, fingers, legs, feet, back or neck? Usually you will feel numbness in your legs if you sit on them for too long. But the numbness and tingling we’re referring to is a bit more complex than that. Something as bizarre as it being an after-effect of radiation therapy can be the answer. The numbness and tingling can be more persistent and bothersome, that you are considering looking for real medical help.