What exactly do contractions feel like?

tmp-9166839

When I had my son 9 years ago, the process happened so fast... plus I was induced. My water never broke on it's own etc. All I can remember was feeling like he was about to fall out and the docs didnt listen to me until they finally checked and realized I was right, he was coming then rather than the next day as they originally stated lol. I didnt have any back pain but my backs been hurting this whole pregnancy

 

Will I feel tightening in my inner vagina, pain in my lower belly? Both? Please explain!!