Sciatic nerve acting up?

So I’ve been maintaining 20-25mpw for just about a month now as I want to build a strong base before my training block actually starts. Every now and again my sciatic nerve will start to bother me, sometimes it eases with stretching, other times it doesn’t ease up until I get a full nights rest. Obviously when it’s acting up I never run on it, sometimes I’ll even give myself an extra day or so to make sure I’ll be ok on my next run.

I’m strength training 3x a week, running 4x a week.

Overall I’m feeling a bit lost on how to prevent these sciatic flair ups and am looking for a bit of seasoned advice! Thank you!!!