Severe back pain&sudden leg numbness like when it falls asleep when change sitting or laying positions cause?hist:coffee table fell on back 2-3yrs ago

Back trauma: Symptoms are consistent with spinal trauma and possible herniated disc. See orthopedic or neurosurgeon if needed after swing primary doc and consider ct and/or MRI of spine.

pinched nerve back: At your age herniated disc causing sciatic pain in leg along with numbness and weakness is likely. See a neurologist. You will likely need MRI scan of low back.