I had a lovely 8k, 9k or 10k route mapped out for today, depending on how I felt after 7k as to which direction I went for my final distance. The weather is great, kids in school and my day off from work so everything set. BUT I have woken up with sacral iliac joint pain in my back and down my right leg, arghh. No idea why it has occurred and not sure if I can or should run today. I am gutted. Anyone have experience of this and how to fix it please?