Motorcycles and Syatic Nerves!

Quick and probably stupid question.
My friend has been diagnosed with a Syatic Nerve in her back.
She’s got some nice pain killers for when she can hardly sit.
We’ve had a debate over whether or not riding her new motorcycle could have triggered it and if she might have to stop riding or just cut down. Does a syatic nerve (pinched) ever go away?
Will riding a motorcycle make it worse because of the vibrations?