hello dear user of HCM! Thank you for your question! Have you done CT scan or MRI of your spine after the injury. Have you talked with the doctor? Since you have had a back injury there are chances to be some damages in your spinal cord or the tissues around it (bones, ligaments, blood vessels etc). They may cause you the numbness and tingling in your feet that may persist until the injury is healed. Sometimes moderate injuries of the lumbar or sacral spinal cord may affect the bowel and bladder. So constipation and urinary disorders may be present. Another cause for the constipation may be oxycodone you take. One of its side effects is constipation. If you haven t done examinations or consultation with the specialist i would highly recommend you to go through a spinal cord MRI and an appointment with a neurologist or neurosurgeon. Take Care and Best Wishes! DR ERIOL.