My 15m won't bend her rt knee she stiffens it & wines when i do it dr said its a pulled muscle shes not walking yet and had shots last week?

Hard to say: It is hard to say without more information. Certainly would be unusual to describe a 15 month old child having knee pain as a "pulled muscle". If it has been persistent, she would be well suited to see an orthopedic surgeon for an exam, X-ray, and potentially other studies.

Get an x-ray: This definitely calls for an x-ray right away, as refusing to bend a limb is a worrisome sign in an infant, especially one that isn't walking yet. If the x-ray is normal, then this could be due to tenderness in the thigh from the vaccinations and it should be safe to give it a week or 10 days with some ibuprofen to heal.