If you use the teeth-whitening strips, and it hurts your teeth, is that ok?

Not really: Whitening strips can increase the sensitivity of teeth. If you have teeth pain for more than a few hour after using the strips, then you should stop.

Yes. : The bleaching solution, carbamide peroxide can cause a temporary increase in tooth sensitivity and mild irritation of the soft tissues of the mouth. Both of these conditions usually are temporary and disappear within 1 to 3 days of stopping or completing treatment. Bleaching is not recommended in children under the age of 16, or for pregnant or lactating women.

Options...: If you have sensitivity, try using a sensitivity toothpaste for a few weeks prior and during whiting.This helps seal the dentinal tubules that cause the sensitivity. It is not advisable to continue strips if you develop severe sensitivity, as you can "overdo it" and cause root damage by not heeding to the symptoms you are feeling. Some sensitivity that subsides in 24 hours is normal.