Hi, I am 7 months pregnant now and I start experiencing belly tightening and hardening.. I want to know what's happening to my unborn baby and if this is normal? Thank u

It sounds like you are experiencing what are known as Braxton-Hicks contractions, your body's "practice" labor contractions.

Braxton Hicks contractions - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Braxton_Hicks_contractions)