I am 28 years old female who just got married 4 mnths ago. since last 20 days i am experiencing numbness, pain and tingling in feet and around knees?

Nerve related: Could be coming from condition of back. There are other possible causes. See your physician.

Congrats on the : Marriage, though I am not sure what that has to do with your medical question. You are describing neuropathy. This maybe secondary to a systemic disease like diabetes, a problem with a vitamin deficiency, a side effect of a particular medication, an issue with nerve impingements in your back etc etc. A neurology consult for emg/ncv's sounds like a good start.