No fun? OP is in an extremely shitty situation.

You're far too sympathetic mate :)

Oh c'mon dude, really? A shitty situation pun? Edit: Ah, guess you realized how badly that'd go over. For your information, you can misdiagnose kidney stones for constipation because both present with abdominal pain.

Lack of cat scan and a doctor that's only half listening or had their mind already made up.

Depending on what the stone was made of, it may not have shown up on an x-ray. Granted they probably should have done a ct scan, but if only an x-ray was performed it's possible they just assumed nothing was there.

As someone that has suffered a kidney stone in the past, it is a unique and unforgettable kind of pain. It is not really abdominal as it begins near the back and works it's way around your flank. I don't know how that could be confused with constipation. I can't say how the passing of the stone goes, though. Mine had to be surgically removed.

Abdominal pain could be just about anything. In my experience, doctors will usually assume constipation first because it's most common and easiest to treat. Often they'll go with a process of elimination method of diagnosis. That method usually works out fine, but unfortunately for OP in this case it didn't.

Don't get me started. My uncle (who has worked at a hospital as a orderly his entire life and is very knowledgable in the medical world because of how long he's worked there) came into the ER in excruciating pain saying he was pretty positive he had appendicitis. They told him he had constipation and sent him home even though he knew it wasn't constitution. He went home and his appendix burst, so he had to be rushed in for emergency surgery and could've easily died because of how bad it was leaking everywhere. I think sometimes, unfortunately, doctors get lazy and feel positive they know what's wrong and would rather take the easy route instead of doing the proper tests. My mom also went in for appendicitis, and they had her go home because they couldn't get a ct scan till the next day, they finally got her ct scan but kept putting back surgery. Her appendix also ruptured and they had no idea until they got in there. Fortunately the leakage was fairly contained and didn't cause problems. Very frustrating.

You might be and idiot who doesn't know what an ultra sound is

I'm sure he knew that just like the rest of the world