Can diastasis recti cause pain in your upper left quadrant?

A repeat mri is not likely to show anything additional. Once you have imaging for an issue unless there is a change or it has been many years repeating the study doesn't show anything new.
Better would be to talk with a surgeon that does diastasis repair or abdominal wall reconstruction.
Things to consider additionally would be inflammation of the cartilage, pinched nerve etc.
Left upper quadrant pain would be a very uncommon symptom of diastasis directly. More likely some form of chronic use injury, old trauma etc. a good physical exam including nerves, ribs and a good history taking may provide some insight.

The most important thing was that you had an MRI to rule out something serious. Hard to know if it’s pain from the diastasis because it usually doesn’t cause pain. Could be a muscle strain but must also consider other non muscular things so you should continue to follow up with your doctor.

Diastasis recti is a splitting of the rectus abdominus muscles which can occur with pregnancy.  It is generally not painful but will cause a weakening of the anterior abdominal wall and laxity.  It is typically repaired in an abdominoplasty procedure.

Dear mamaof2sweetboys,
diastasis recti is a separation of abdominal muscles and it causes no pain or discomfort. If you have rib discomfort, then I suggest you to consult your doctor and get an examination. 
Daniel Barrett, MD

Diastasis recti is not a painful condition as there is muscle separation but no hernia. Also this is in the midline of your abdomen. If you are having abdominal pain on the left side under the rib cage a review by your primary health care provider is the way forwards. This will ensure that there is no serious underlying bowel or internal issue.

Diastases recti is the stretching of the linea alba, which is a line of tissue between the two vertical rows of your rectus muscles. The stretching of this tissue causes weakness of the abdominal wall and a pooching affect of the tummy. This cannot be improved with exercise. DR is not a hernia and therefore does not have to be fixed. Diastases recti is not a painful problem and it’s not the source of your rib pain. Intercostal muscle strains or costochondritis (inflammation of the cartilage) is most likely your problem. This is diagnosed by symptoms and MRI will not show anything. I think rest, anti-inflammatory meds, and a Chiropractor would be best for you. Hope that helps. 

Diastasis Recti is basically a gap that occurs between the 2 rectus abdominis muscles.  These are 2 very big muscles that originate from the rib cage and insert on the pubic bone.  There are wide, about 4-5 cm, and basically are touching in the midline.  When there is a lot of pressure from inside the abdomen (pregnancy, weight gain), the muscles can drift apart, leaving a gap in the midline.  It is not a hernia and does not cause any pain or discomfort.  It is unlikely that your pain has anything to do with the diastasis recti.  This may be more of a rib issue, it should dissipate with time, I would save the money from another MRI, the yield from repeating this test would not be high.Good Luck!