Fell 8 months ago, upperback/whiplash cause tight muscles in back and chest? I have both chest and back pain constantly. Already seen my Doc 7 times

See below. There are many potential causes of acute neck pain. The most common causes are related to strain or injury to the mucles and/or structures of the spine. The pain should improve within 2-3 weeks. Ask your doc to refer you to a spine specialist for further evaluation and treatment.
Back pain . Try getting some physical therapy or seeing a chiropractor.... Pain cream/ lotions are available, which can be costly, but if covered by insurance are a good choice due to the zero risk of addiction .