Titanium rod in left leg hurting badly what can i do to make it stop?

You must see the surgeon who put it in. In the meantime, avoid heavy excercise involving that leg and take ibuprofen for pain.

Titanium is inert and should not in and of itself cause pain. You should see your surgeon and have an x-ray. Your fracture may not have healed, hardware failed or come loose or have other sources of pain. In the interim, rest the leg (avoid excessive weight bearing).