Hello,
Thankyou for your question.
Brief..It could be slip disc at S1 level of spine.
Detailed answer..
It seems that you have problem of slip disc of spine at S1 level.Since disc remains in between two vertebrae and from the side of disc nerves emerge to supply respective areas.As From your accident history ,it can be because of old injury or increased weight or lifting heavy weight etc
In my opinion you should go for
MRI spine and discuss further with neurosurgeon.As after looking at MRI a neurosurgeon can conclude that how much nerves are getting irritated because of disc and what should be the optimum treatment further,it can be treated by some exercises,
physiotherapy,pain killers.But in the worst situation means if
nerve injury is enough causing change in sensation like yours,or
incontinence problem then surgery can be the option for further treatment after discussing with neurosurgeon.
Hopefully my answer is helpfull.You may ask further without any hesitation.
Regards,
Dr.Maheshwari