I'm having extreme pain in my right knee wich travels down my leg in a straight line more painfully at night and when I'm lest active?

Nerve pain. You may be experiencing some nerve pain possibly aggravated by pressure on the nerve root from disc disease or musculoskeletal disease. I would suggest seeing your primary care doctor to see about additional tests.
Eval. Question becomes is pain coming from the knee itself or is it referred pain fro other structure in the body. Formal eval by physician may be beneficial to determine the source of pain and recommend a treament plan specific for that cause.