Hi, Thank you for posting your query!
As per what you have mentioned it seems your are suffering for an whiplash injury
of neck which occurs following accident where your neck bones moves backwards and forwards rupturing the joints and surrounding tissues. Depending on the severity of your condition you should consult an orthopedic for medications and physical therapist for proper rehabilitation
of your spine.
Your major concern right now for me is your leg discrepancy, which shows pelvic dysfunction
and due to this you can have back pain
and walking issues.
Consult a Physical Therapist, he/she can guide you with some exercises and manual therapy for correcting your spinal dysfunction
with proper screening of your problem.
Hope i have answered your query please feel feel to get back with further queries.