For me it felt like waves of severe menstrual cramps, along with a tightening of my belly. Started minor and ramped up, rhythmically, getting longer and closer together.

Also mine started in lower abdomen and went around to my hips and lower back

It felt like my skin was tightening and ripping apart while on fire and being stabbed with knives.

Contractions are more rhythmic and less spontaneous. They will feel like more intense period cramps and your whole body might tense and stop you in your tracks.

I have a high tolerance too and didn't know I was in labor till my water broke. But looking back it makes sense. I was woken out of my sleep by cramping.

I have a hugely high pain tolerance as well. I can’t go by the “you’ll know” or “if you can’t walk/talk through it”. For me, my whole stomach became hard and tight, then released.