Do you suffer from any underlying health conditions such as diabetes?
It is important to understand that sciatica can unfortunately be chronic and the best treatment is a carefully tailored approach.
I would recommend really focusing on the lower back muscles in improving strength while also flexibility. Movement is key so continue with the exercise in the mornings.
Exercise releases endorphins which reduce inflammation.
Focus on building up lower limb strength with resistance training and avoid static positions longer than 45 minutes.