How much time does one generally have pain, specifically nerve pain with sciatica?

4-6 weeks. Initially the symptoms last 4-6 weeks and if your body heals like it supposed to then pain relief starts. However disc herniations which are the cause of majority of sciatica symptoms last for 6-9 months and therefore people can have pain during that time as well. If not better after 6 weeks see a spine specialist to evaluate this further.
Depends. It all depends if the cause remains inflaming the nerve. It can take weeks months to even years. Oral or injected steroids can help. .