I sustained a 5th metatarsal avultion break non-jones 8.5 weeks ago. x ray showed partial healing.also, new burning pain underfoot. is it normal?

Maybe: The new burning pain may need evaluation - you may have plantar fasciitis due to treatment/disuse of the fractured foot. A 5th metatarsal fracture as you have described can take upwards of 10 - 12 weeks to show good healing on an x-ray, but in most cases that type of fracture should heal 100% and you should not have any long term problems.

Pain/Fracture: Burning type pain for this type of break is not what i would consider normal unless it started from the day of the initial injury. 8..5 weeks is a while to show only partial healing. Report this to your doctor.