Ladies that have done labour without induction

Deb
Baby no 4. However never had labour naturally. Induced once rest c section. I have had diarrhoea for 2 days. I'm not unwell no stomach bug. Back ache and pulling in top of thighs. Could this be a sign labour on way or just one of those things. Never had it in any pregnancy. I'm only 35 weeks. C section booked for 39 weeks 30th Sep