Hundreds of threads here on DW and shimmies/shakes.
With the limited info you provided, we are shooting in the dark with any idea or answer we provide.
Do some research... search this forum and others, understand the causes and symptoms, try to narrow your causes down a bit
Look for threads that have similarities to your situation, review for potential causes and cures that worked.
Then come back with some clarity on your situation, so others can help you.