What level of pain should be expected two weeks post op from an l4-l5 fusion with a cage and screws and a bone graft from my hip.

Varies: Unfortunately there is not one correct answer. In other words, some patients will have very little or even no pain, whereas other patients will continue to have severe pain. Also unfortunately, a bone graft from the hip is a well known cause of postop pain which can be persistent. If your pain is really severe, you should of course see your surgeon and have x-rays and an examination.