Hi i suggest an ultrasound also.
The least painful procedure, as theres no pain at all, just a little pressure =)

I too had this stabbing pain, well i still do infact, for another 4 days anyways =| hopefully.

When i had my ultrasound it showed that i had a fluid build up which was larger than its suppose to be, i got this on my right side, in my lower abdomen. It takes your breath away doesn't it, you get scared to breathe and its feels that you are being sliced.
I had that quite alot, but my fluid build up has gone down a bit now compared to what it was. But im still getting pain, but i feel as if this is a different pain to the build up. This pain i get feels that its the end of the tube trying to stick out of me as its in my pelvic region in between my hips. This ive been getting EVERY day since my distal end was inserted lower than a previous incision in a distal revision due to migration. My last revision was in SEPTEMBER! its now the end of FEB! So it could well be down to the catheter irritating.

There is them two possibilites, but it may also be down to adhesions, scar tissue.

My neurosurgeon has tested me for infection of the peritoneum which came back clear after having an abdominal aspiration, which was a needle, a big needle at that that punctures through all the layers of your body to get into the fluid in your cavity to test the CSF. Which may also be a test which you should undergo for infection.
I must say the first time i had it done, it was over in 10/15 mins, start to finish including prep and clean up. The second time i had it done, it was the worst experience of my life, its done under local anesthetic. You cant imagine the pain it causes, there is resistance to each layer in your body, skin, muscles, peritoneum, cavity and the fluid and other layers, each layer can be felt being punctured. On the second go this was done so so many times over as they couldnt get to the fluid due to bowel movement, they had to make a small incision to get a bigger needle in, i came out of it traumatised, seriously.
So if you have it done, have it under GENERAL ANESTHETIC!!

Well anyways, my neurosurgeon now has me down for a conversion of my VP to a VA, where the catheter will go into my heart instead of the abdomen.
This should stop the fluid build up and also the irritation of the tube. It wont help with adhesional pain, so im hoping the pain is being caused by either the fluid or catheter!!!

Good luck!!!