Originally Posted by
JustTony 
As you have said anxiety can be the cause of very similar symptoms.
The other thing that causes incredibly similar pain and hardness of the core is trapped air. Normally this abates after a couple of days though - unless you have a permanent blockage or diet that causes excess gas?
Other than those thoughts I could only suggest you seek second and third opinions from a medical practitioner?
I do have some trapped gas in my colon according to x-rays - but my bowel movements are regular.
I've been to every ER in the city and half the immediate cares and several different specialists.