As you had a cat scan with contrast dye and it didn't find anything and didn't show up as the lump being a hernia, then you do not have a hernia. It if was a hernia it would have shown up.
A hernia is when the bowel wall breaks and this protrudes.
It is more likely to be a fatty cyst or a ganglion.
If it is still bothering you your doctor can refer you to have it removed.
I know its some kind of hernia but my Doctor said it is in a spot where he has never seen one. I had a cat scan last week and didn't find anything. Thank you for replying
The lump doesn't stay out i can push it back under my left rib and it is very painful. I had a cat scan with contrast last week and it didn't find a hernia. Thank you replying
Is it painful to the touch? When you feel it, does it feel "spongy"
I think if it continues to stay, you should see another doctor, ask for an ultra-sound and if nothing is found, then see a chiropractor, this could be a misaligned vertebrae, I have had similar issues and as soon as I was "adjusted" they went away.
Why don't you make an appointment and see the doctor again and ask him to refer you to someone who will be able to check you out and do the appropriate tests to find out what it is.
Having an ultrasound scan would be a start or send you to a specialist so that they can take a sample for testing.
It may be a ganglion cyst, but you do need the appropriate investigation and not just be told that they don't know what it is.