Lower left-sided back pain

[LadyPN1]

This is about my God-daughter who is 13. When she was five her spleen had to be removed which required her to be on special meds all her life to combat her lack of immunity. For several weeks now she has been complaining of pain in her side in the back. Sometimes it does affect her mobility. Doctors had her tested for drugs and pregnancy for some reason but that was ruled out. Then they order an MRI but found no kidney stones. They did find some liquid around the area  I'm not sure exactly where. At any rate, they sent her home and said there was nothing wrong and she should just take it easy for a bit. Because of her history of lack of immunity and special meds, I am concerned that they didn't do further tests. Do you have any input?

[kittyluv1]

It is difficult to determine whether additional testing needs to be done based on the information provided.  If you could provide a more detailed explanation of her symptoms it would be helpful. Describe the back pain and how it is affecting her mobility. Are there any associated symptoms such as leg pain?
Was the MRI done of her lumbar spine?  If you have the written report of the MRI it would be helpful for you to post the findings as noted by the radiologist.  We may be able to interpret the medical jargon to make the findings more understandable in layman's language.
The removal of her spleen did place her at higher risk for secondary infections, but the administration of antibiotics and getting proper immunizations for flu, pneumonia etc should be effective in prevention.  
Back pain localized in the side and below the ribs could be related to the presence of kidney stones but other symptoms would likely be present such as pain on urination and nausea/vomiting.
They tested her for pregnancy as pain presenting in this way might be indicative of an ectopic pregnancy, which is a medical emergency.
Post with updated information and we will try and assist you further.