Is it normal to have cramps in the 3rd trimester?

Yes. There are 3 common causes of cramps in the 3rd trimester. Round ligament pain is pain in the structures supporting the uterus, often in the groin. Braxton-hicks contractions are "practice" contractions, when the uterus tightens or cramps periodically but they aren't regular. Labor can also cause cramping contractions every 3-5 minutes that don't go away with rest and hydration.
Yes. Episodic uterine cramps and contractions are normal in the third trimester. If you are contracting more than 3 or 4 times an hour for more than one hour before 34 weeks, you should go to l&d. After 34 weeks you can wait until contractions are closer (10 minutes or less) for a couple hours.

Related Questions

I'm in my 3rd trimester & I have notice that when im sleeping on either side my arms go numb, & I have been having some leg cramps. Is it normal?

Staypuff marshmellow. At this stage in pregnancy you are carrying a heavy child, and an enormous amount of circulatory fluid and extra blood so when you sleep on your arm, it too "goes to sleep" from the pressure and temporary obstruction of circulation and nerve compression. Use pillows liberally and change positions often to avoid the problem.