Shuffle not working properly
I've got a few thousand songs on my iPhone, but for some reason shuffle will only play a selection of them, the same selection every time (no more than 100) - the rest of the songs seem to be forgotten even though they are there. They are downloaded and synced, I'm using 'songs' not a particular playlist, and they will play if I specifically tell them to, so there doesn't seem to be any reason for them not to be included in shuffle. I can guarantee if I do it right now, I'll hear the same songs I heard yesterday, and the day before, and the day before that... you get the picture, and I have to keep on pressing skip for several minutes before it will eventually play something I haven't heard for a while. Does anyone know how to solve this please?
iPhone 8