kidneys, really bad stomach pain after urination?

Morgan1989- Believe it or not, I used to go through something similar to what you are describing. However, because there is so little detail in your question it is difficult to answer.
I had pain in my lower left abdomen that would get very intense after urinating. However, I did have a general level of intermitent pain and had "flare ups" after urinating. I battled infections until I was in constant pain. I was misdiagnosed 12 times over a year and a half before I was admitted into the hospital due to an ifection that required immediate and prolonged treatment. It was then that they found a blockage/scar tissue in the kidney, and the kidney was no longer functioning.
I am not suggesting that this is what you might have as much as it is possible that it could be abdominal pain that is a symptom and result of a kidney problem.
Where the pain is localized at might help to determine what could possibly be the cause with greater accuracy. There are many types of conditions that could cause pain in the abdomen after urinating, such as UTI, bladder issues, PFD (pelvic floor dysfunction), etc.
In any case, consult with a physician.
I hope this helps. Good luck to you.