Hi there. You need to be examined clinically by a neurologist for possible trauma to the vertebral spines, fracture vertebra, nerve root impingement, prolapsed intervertebral disc etc. this might require an MRI Spine to confirm the injury. Treatment would depend on the cause and diagnosis. This may include immobilization, bed rest, systemic NSAIDS and opioids. Surgical correction might be required depending on the MRI findings. Take care.
You could have brusied, fractured or even broke something. You need to see your doc. Back injuries arent something you want to mess with.